diff --git a/src/sentry/workflow_engine/models/action.py b/src/sentry/workflow_engine/models/action.py
index 1ea85bcd66dbc5..90b8a7c9d1a7e8 100644
--- a/src/sentry/workflow_engine/models/action.py
+++ b/src/sentry/workflow_engine/models/action.py
@@ -124,9 +124,9 @@ def get_handler(self) -> builtins.type[ActionHandler]:
         return action_handler_registry.get(action_type)
 
     def trigger(self, event_data: WorkflowEventData, notification_uuid: str) -> None:
-        from sentry.workflow_engine.processors.detector import get_detector_from_event_data
+        from sentry.workflow_engine.processors.detector import get_preferred_detector
 
-        detector = get_detector_from_event_data(event_data)
+        detector = get_preferred_detector(event_data)
 
         with metrics.timer(
             "workflow_engine.action.trigger.execution_time",
diff --git a/src/sentry/workflow_engine/processors/detector.py b/src/sentry/workflow_engine/processors/detector.py
index 9eb296d74743b0..ff83dc3ba8b8bf 100644
--- a/src/sentry/workflow_engine/processors/detector.py
+++ b/src/sentry/workflow_engine/processors/detector.py
@@ -258,8 +258,9 @@ def detectors(self) -> set[Detector]:
         return {d for d in [self.issue_stream_detector, self.event_detector] if d is not None}
 
 
-def get_detectors_for_event(
-    event_data: WorkflowEventData, detector: Detector | None = None
+def get_detectors_for_event_data(
+    event_data: WorkflowEventData,
+    detector: Detector | None = None,
 ) -> EventDetectors | None:
     """
     Returns a list of detectors for the event to process workflows for.
@@ -267,8 +268,7 @@ def get_detectors_for_event(
     We always return at least the issue stream detector, unless excluded via option.
     If the event has an associated detector, we return it too.
 
-    If the detector is passed in, use that instead of searching for a detector.
-    This is used for Activity updates.
+    We expect a detector to be passed in for Activity updates.
     """
     issue_stream_detector: Detector | None = None
     exclude_issue_stream = options.get("workflow_engine.exclude_issue_stream_detector")
@@ -288,9 +288,9 @@ def get_detectors_for_event(
                 },
             )
 
-    if detector is None:
+    if detector is None and isinstance(event_data.event, GroupEvent):
         try:
-            detector = get_detector_by_event(event_data)
+            detector = _get_detector_for_event(event_data.event)
         except Detector.DoesNotExist:
             pass
 
@@ -300,24 +300,20 @@ def get_detectors_for_event(
         return None
 
 
-def get_detector_by_event(event_data: WorkflowEventData) -> Detector:
-    evt = event_data.event
-
-    if not isinstance(evt, GroupEvent):
-        raise TypeError(
-            "Can only use `get_detector_by_event` for a new event, Activity updates are not supported"
-        )
+def _get_detector_for_event(event: GroupEvent) -> Detector:
+    """
+    Returns the detector from the GroupEvent in event_data.
+    """
 
-    issue_occurrence = evt.occurrence
+    issue_occurrence = event.occurrence
 
     try:
-        if issue_occurrence is None or evt.group.issue_type.detector_settings is None:
-            # if there are no detector settings, default to the error detector
-            detector = Detector.get_error_detector_for_project(evt.project_id)
-        else:
+        if issue_occurrence is not None:
             detector = Detector.objects.get(
                 id=issue_occurrence.evidence_data.get("detector_id", None)
             )
+        else:
+            detector = Detector.get_error_detector_for_project(event.group.project_id)
     except Detector.DoesNotExist:
         metrics.incr("workflow_engine.detectors.error")
         detector_id = (
@@ -327,8 +323,8 @@ def get_detector_by_event(event_data: WorkflowEventData) -> Detector:
         logger.exception(
             "Detector not found for event",
             extra={
-                "event_id": evt.event_id,
-                "group_id": evt.group_id,
+                "event_id": event.event_id,
+                "group_id": event.group_id,
                 "detector_id": detector_id,
             },
         )
@@ -337,7 +333,7 @@ def get_detector_by_event(event_data: WorkflowEventData) -> Detector:
     return detector
 
 
-def get_detector_by_group(group: Group) -> Detector:
+def _get_detector_for_group(group: Group) -> Detector:
     """
     Returns Detector associated with this group, either based on DetectorGroup,
     (project, type), or if those fail, returns the Issue Stream detector.
@@ -360,12 +356,18 @@ def get_detector_by_group(group: Group) -> Detector:
         return Detector.objects.get(project_id=group.project_id, type=IssueStreamGroupType.slug)
 
 
-def get_detector_from_event_data(event_data: WorkflowEventData) -> Detector:
+def get_preferred_detector(event_data: WorkflowEventData) -> Detector:
+    """
+    Attempts to fetch the specific detector based on the GroupEvent or Activity in event_data
+    """
     try:
         if isinstance(event_data.event, GroupEvent):
-            return get_detector_by_event(event_data)
+            event_detectors = get_detectors_for_event_data(event_data)
+            if event_detectors is None:
+                raise Detector.DoesNotExist("No detectors found for event")
+            return event_detectors.preferred_detector
         elif isinstance(event_data.event, Activity):
-            return get_detector_by_group(event_data.group)
+            return _get_detector_for_group(event_data.group)
         else:
             raise TypeError(f"Cannot determine the detector from {type(event_data.event)}.")
     except Detector.DoesNotExist:
diff --git a/src/sentry/workflow_engine/processors/workflow.py b/src/sentry/workflow_engine/processors/workflow.py
index f0695206c46421..5d3eaf42c10944 100644
--- a/src/sentry/workflow_engine/processors/workflow.py
+++ b/src/sentry/workflow_engine/processors/workflow.py
@@ -1,4 +1,4 @@
-from collections.abc import Collection, Sequence
+from collections.abc import Sequence
 from dataclasses import asdict, replace
 from datetime import datetime
 from enum import StrEnum
@@ -30,7 +30,7 @@
     get_data_conditions_for_group,
     process_data_condition_group,
 )
-from sentry.workflow_engine.processors.detector import get_detectors_for_event
+from sentry.workflow_engine.processors.detector import get_detectors_for_event_data
 from sentry.workflow_engine.processors.workflow_fire_history import create_workflow_fire_histories
 from sentry.workflow_engine.types import (
     WorkflowEvaluation,
@@ -380,7 +380,7 @@ def get_environment_by_event(event_data: WorkflowEventData) -> Environment | Non
 
 @scopedstats.timer()
 def _get_associated_workflows(
-    detectors: Collection[Detector], environment: Environment | None, event_data: WorkflowEventData
+    detector: Detector, environment: Environment | None, event_data: WorkflowEventData
 ) -> set[Workflow]:
     """
     This is a wrapper method to get the workflows associated with a detector and environment.
@@ -394,7 +394,7 @@ def _get_associated_workflows(
     workflows = set(
         Workflow.objects.filter(
             environment_filter,
-            detectorworkflow__detector_id__in=[detector.id for detector in detectors],
+            detectorworkflow__detector_id=detector.id,
             enabled=True,
         )
         .select_related("environment")
@@ -421,7 +421,7 @@ def _get_associated_workflows(
                 "event_data": asdict(event_data),
                 "event_environment_id": environment.id if environment else None,
                 "workflows": [workflow.id for workflow in workflows],
-                "detector_types": [detector.type for detector in detectors],
+                "detector_type": detector.type,
             },
         )
 
@@ -454,7 +454,7 @@ def process_workflows(
     )
 
     try:
-        event_detectors = get_detectors_for_event(event_data, detector)
+        event_detectors = get_detectors_for_event_data(event_data, detector)
 
         if not event_detectors:
             raise Detector.DoesNotExist("No Detectors associated with the issue were found")
@@ -500,7 +500,9 @@ def process_workflows(
     if features.has("organizations:workflow-engine-process-workflows-logs", organization):
         log_context.set_verbose(True)
 
-    workflows = _get_associated_workflows(event_detectors.detectors, environment, event_data)
+    workflows = _get_associated_workflows(
+        event_detectors.preferred_detector, environment, event_data
+    )
     workflow_evaluation_data.workflows = workflows
 
     if not workflows:
diff --git a/src/sentry/workflow_engine/tasks/actions.py b/src/sentry/workflow_engine/tasks/actions.py
index b00386e4bf13b6..de7c3c180db6a5 100644
--- a/src/sentry/workflow_engine/tasks/actions.py
+++ b/src/sentry/workflow_engine/tasks/actions.py
@@ -91,7 +91,7 @@ def trigger_action(
     import uuid
 
     from sentry.notifications.notification_action.utils import should_fire_workflow_actions
-    from sentry.workflow_engine.processors.detector import get_detector_from_event_data
+    from sentry.workflow_engine.processors.detector import get_preferred_detector
 
     # Generate UUID if not provided (handles version skew at task boundary)
     if notification_uuid is None:
@@ -129,7 +129,7 @@ def trigger_action(
         )
         raise ValueError("Exactly one of event_id or activity_id must be provided")
 
-    detector = get_detector_from_event_data(event_data)
+    detector = get_preferred_detector(event_data)
 
     metrics.incr(
         "workflow_engine.tasks.trigger_action_task_started",
diff --git a/tests/sentry/workflow_engine/models/test_action.py b/tests/sentry/workflow_engine/models/test_action.py
index bbc05731f8e7e0..0310d88c23f3dc 100644
--- a/tests/sentry/workflow_engine/models/test_action.py
+++ b/tests/sentry/workflow_engine/models/test_action.py
@@ -71,7 +71,7 @@ def test_get_handler_unregistered_type(self) -> None:
             # Verify the registry was queried with the correct action type
             mock_get.assert_called_once_with(Action.Type.SLACK)
 
-    @patch("sentry.workflow_engine.processors.detector.get_detector_from_event_data")
+    @patch("sentry.workflow_engine.processors.detector.get_preferred_detector")
     def test_trigger_calls_handler_execute(self, mock_get_detector: MagicMock) -> None:
         mock_handler = Mock(spec=ActionHandler)
         mock_detector = Mock(spec=Detector, type="error")
@@ -88,7 +88,7 @@ def test_trigger_calls_handler_execute(self, mock_get_detector: MagicMock) -> No
             assert invocation.action == self.action
             assert invocation.detector == mock_detector
 
-    @patch("sentry.workflow_engine.processors.detector.get_detector_from_event_data")
+    @patch("sentry.workflow_engine.processors.detector.get_preferred_detector")
     def test_trigger_with_failing_handler(self, mock_get_detector: MagicMock) -> None:
         mock_handler = Mock(spec=ActionHandler)
         mock_handler.execute.side_effect = Exception("Handler failed")
@@ -99,7 +99,7 @@ def test_trigger_with_failing_handler(self, mock_get_detector: MagicMock) -> Non
                 self.action.trigger(self.mock_event, notification_uuid=str(uuid.uuid4()))
 
     @patch("sentry.utils.metrics.incr")
-    @patch("sentry.workflow_engine.processors.detector.get_detector_from_event_data")
+    @patch("sentry.workflow_engine.processors.detector.get_preferred_detector")
     def test_trigger_metrics(self, mock_get_detector: MagicMock, mock_incr: MagicMock) -> None:
         mock_handler = Mock(spec=ActionHandler)
         mock_get_detector.return_value = Mock(spec=Detector, type="error")
diff --git a/tests/sentry/workflow_engine/processors/test_detector.py b/tests/sentry/workflow_engine/processors/test_detector.py
index 72345176eefa91..cbc58dfebf2c99 100644
--- a/tests/sentry/workflow_engine/processors/test_detector.py
+++ b/tests/sentry/workflow_engine/processors/test_detector.py
@@ -30,8 +30,8 @@
 from sentry.workflow_engine.processors.detector import (
     associate_new_group_with_detector,
     ensure_association_with_detector,
-    get_detector_by_event,
-    get_detectors_for_event,
+    get_detectors_for_event_data,
+    get_preferred_detector,
     process_detectors,
 )
 from sentry.workflow_engine.types import (
@@ -838,7 +838,7 @@ class TestGetDetectorsForEvent(TestCase):
     def setUp(self) -> None:
         super().setUp()
         self.project = self.create_project()
-        self.group = self.create_group(project=self.project)
+        self.group = self.create_group(project=self.project, type=MetricIssue.type_id)
         self.detector = self.create_detector(project=self.project, type=MetricIssue.slug)
         self.error_detector = self.create_detector(project=self.project, type=ErrorGroupType.slug)
         self.issue_stream_detector = self.create_detector(
@@ -871,7 +871,7 @@ def test_activity_update(self) -> None:
             user_id=self.user.id,
         )
         event_data = WorkflowEventData(event=activity, group=self.group)
-        result = get_detectors_for_event(event_data, detector=self.detector)
+        result = get_detectors_for_event_data(event_data, detector=self.detector)
         assert result is not None
         assert result.preferred_detector == self.detector
         assert result.detectors == {self.issue_stream_detector, self.detector}
@@ -879,7 +879,7 @@ def test_activity_update(self) -> None:
     @override_options({"workflow_engine.exclude_issue_stream_detector": False})
     def test_error_event(self) -> None:
         event_data = WorkflowEventData(event=self.group_event, group=self.group)
-        result = get_detectors_for_event(event_data)
+        result = get_detectors_for_event_data(event_data)
         assert result is not None
         assert result.preferred_detector == self.error_detector
         assert result.detectors == {self.issue_stream_detector, self.error_detector}
@@ -889,7 +889,7 @@ def test_metric_issue(self) -> None:
         self.group_event.occurrence = self.occurrence
 
         event_data = WorkflowEventData(event=self.group_event, group=self.group)
-        result = get_detectors_for_event(event_data)
+        result = get_detectors_for_event_data(event_data)
         assert result is not None
         assert result.preferred_detector == self.detector
         assert result.detectors == {self.issue_stream_detector, self.detector}
@@ -914,7 +914,7 @@ def test_event_without_detector(self) -> None:
         self.group_event.occurrence = occurrence
 
         event_data = WorkflowEventData(event=self.group_event, group=self.group)
-        result = get_detectors_for_event(event_data)
+        result = get_detectors_for_event_data(event_data)
         assert result is not None
         assert result.preferred_detector == self.issue_stream_detector
         assert result.detectors == {self.issue_stream_detector}
@@ -923,14 +923,14 @@ def test_no_detectors(self) -> None:
         self.issue_stream_detector.delete()
         self.error_detector.delete()
         event_data = WorkflowEventData(event=self.group_event, group=self.group)
-        result = get_detectors_for_event(event_data)
+        result = get_detectors_for_event_data(event_data)
         assert result is None
 
     def test_exclude_issue_stream_detector(self) -> None:
         event_data = WorkflowEventData(event=self.group_event, group=self.group)
 
         # Default behavior: issue stream detector is included
-        result = get_detectors_for_event(event_data)
+        result = get_detectors_for_event_data(event_data)
 
         assert result is not None
         assert result.issue_stream_detector == self.issue_stream_detector
@@ -939,7 +939,7 @@ def test_exclude_issue_stream_detector(self) -> None:
 
         # With flag enabled: issue stream detector is excluded
         with override_options({"workflow_engine.exclude_issue_stream_detector": True}):
-            result_excluded = get_detectors_for_event(event_data)
+            result_excluded = get_detectors_for_event_data(event_data)
 
             assert result_excluded is not None
             assert result_excluded.issue_stream_detector is None
@@ -947,10 +947,10 @@ def test_exclude_issue_stream_detector(self) -> None:
             assert result_excluded.preferred_detector == self.error_detector
 
 
-class TestGetDetectorByEvent(TestCase):
+class TestGetPreferredDetector(TestCase):
     def setUp(self) -> None:
         super().setUp()
-        self.group = self.create_group(project=self.project)
+        self.group = self.create_group(project=self.project, type=MetricIssue.type_id)
         self.detector = self.create_detector(project=self.project, type=MetricIssue.slug)
         self.error_detector = self.create_detector(project=self.project, type=ErrorGroupType.slug)
         self.event = self.store_event(project_id=self.project.id, data={})
@@ -976,32 +976,35 @@ def test_with_occurrence(self) -> None:
 
         event_data = WorkflowEventData(event=group_event, group=self.group)
 
-        result = get_detector_by_event(event_data)
+        result = get_preferred_detector(event_data)
 
         assert result == self.detector
 
     def test_without_occurrence(self) -> None:
+        self.group.type = ErrorGroupType.type_id
         group_event = GroupEvent.from_event(self.event, self.group)
         group_event.occurrence = None
 
         event_data = WorkflowEventData(event=group_event, group=self.group)
 
-        result = get_detector_by_event(event_data)
+        result = get_preferred_detector(event_data)
 
         assert result == self.error_detector
 
-    def test_activity_not_supported(self) -> None:
+    def test_activity(self) -> None:
         activity = Activity.objects.create(
             project=self.project,
             group=self.group,
             type=ActivityType.SET_RESOLVED.value,
             user_id=self.user.id,
         )
+        DetectorGroup.objects.create(detector=self.detector, group=self.group)
 
         event_data = WorkflowEventData(event=activity, group=self.group)
 
-        with pytest.raises(TypeError):
-            get_detector_by_event(event_data)
+        result = get_preferred_detector(event_data)
+
+        assert result == self.detector
 
     def test_no_detector_id(self) -> None:
         occurrence = IssueOccurrence(
@@ -1026,9 +1029,9 @@ def test_no_detector_id(self) -> None:
         event_data = WorkflowEventData(event=group_event, group=self.group)
 
         with pytest.raises(Detector.DoesNotExist):
-            get_detector_by_event(event_data)
+            get_preferred_detector(event_data)
 
-    def test_defaults_to_error_detector(self) -> None:
+    def test_errors_on_no_detector(self) -> None:
         occurrence = IssueOccurrence(
             id=uuid.uuid4().hex,
             project_id=self.project.id,
@@ -1051,9 +1054,8 @@ def test_defaults_to_error_detector(self) -> None:
 
         event_data = WorkflowEventData(event=group_event, group=self.group)
 
-        result = get_detector_by_event(event_data)
-
-        assert result == self.error_detector
+        with pytest.raises(Detector.DoesNotExist):
+            get_preferred_detector(event_data)
 
 
 class TestAssociateNewGroupWithDetector(TestCase):
diff --git a/tests/sentry/workflow_engine/processors/test_workflow.py b/tests/sentry/workflow_engine/processors/test_workflow.py
index ed5779bf8b4cb8..239ae81c1b81f7 100644
--- a/tests/sentry/workflow_engine/processors/test_workflow.py
+++ b/tests/sentry/workflow_engine/processors/test_workflow.py
@@ -6,6 +6,7 @@
 
 from sentry.eventstream.base import GroupState
 from sentry.grouping.grouptype import ErrorGroupType
+from sentry.incidents.grouptype import MetricIssue
 from sentry.models.activity import Activity
 from sentry.models.environment import Environment
 from sentry.services.eventstore.models import GroupEvent
@@ -63,7 +64,9 @@ def setUp(self) -> None:
             )
         )
 
-        self.group, self.event, self.group_event = self.create_group_event()
+        self.group, self.event, self.group_event = self.create_group_event(
+            group_type_id=MetricIssue.type_id
+        )
         self.event_data = WorkflowEventData(
             event=self.group_event,
             group=self.group,
@@ -304,6 +307,7 @@ def test_same_environment_only(self) -> None:
     def test_issue_occurrence_event(self) -> None:
         issue_occurrence = self.build_occurrence(evidence_data={"detector_id": self.detector.id})
         self.group_event.occurrence = issue_occurrence
+        self.group_event.group.type = issue_occurrence.type.type_id
 
         result = process_workflows(self.batch_client, self.event_data, FROZEN_TIME)
         assert result.data.triggered_workflows == {self.workflow}
@@ -464,8 +468,8 @@ def test_uses_issue_stream_workflows(self) -> None:
         assert len(result.data.triggered_actions) == 0
 
     @override_options({"workflow_engine.exclude_issue_stream_detector": False})
-    def test_multiple_detectors(self) -> None:
-        issue_stream_workflow, issue_stream_detector, _, _ = self.create_detector_and_workflow(
+    def test_multiple_detectors__preferred(self) -> None:
+        _, issue_stream_detector, _, _ = self.create_detector_and_workflow(
             name_prefix="issue_stream",
             workflow_triggers=self.create_data_condition_group(),
             detector_type=IssueStreamGroupType.slug,
@@ -476,7 +480,7 @@ def test_multiple_detectors(self) -> None:
         )
 
         result = process_workflows(self.batch_client, self.event_data, FROZEN_TIME)
-        assert result.data.triggered_workflows == {self.error_workflow, issue_stream_workflow}
+        assert result.data.triggered_workflows == {self.error_workflow}
         assert result.data.associated_detector == self.error_detector
 
 
@@ -670,6 +674,7 @@ class TestWorkflowEnqueuing(BaseWorkflowTest):
     buffer_timestamp = (FROZEN_TIME + timedelta(seconds=1)).timestamp()
 
     def setUp(self) -> None:
+        self.project = self.create_project(create_default_detectors=True)
         (
             self.workflow,
             self.detector,
@@ -679,7 +684,7 @@ def setUp(self) -> None:
 
         occurrence = self.build_occurrence(evidence_data={"detector_id": self.detector.id})
         self.group, self.event, self.group_event = self.create_group_event(
-            occurrence=occurrence,
+            occurrence=occurrence, group_type_id=MetricIssue.type_id
         )
         self.event_data = WorkflowEventData(event=self.group_event, group=self.group)
         self.action_group, _ = self.create_workflow_action(self.workflow)
@@ -877,17 +882,23 @@ def setUp(self) -> None:
         ) = self.create_detector_and_workflow()
 
         self.action_group, self.action = self.create_workflow_action(workflow=self.workflow)
+        self.issue_stream_detector = self.create_detector(
+            project=self.project,
+            type=IssueStreamGroupType.slug,
+        )
 
         self.group, self.event, self.group_event = self.create_group_event(
-            occurrence=self.build_occurrence(evidence_data={"detector_id": self.detector.id})
+            occurrence=self.build_occurrence(evidence_data={"detector_id": self.detector.id}),
+            group_type_id=MetricIssue.type_id,
         )
         self.event_data = WorkflowEventData(event=self.group_event, group=self.group)
         self.batch_client = DelayedWorkflowClient()
 
     @patch("sentry.utils.metrics.incr")
     @patch("sentry.workflow_engine.tasks.utils.IssueOccurrence.fetch")
+    @patch("sentry.workflow_engine.processors.action.Action.trigger")
     def test_metrics_issue_dual_processing_metrics(
-        self, mock_fetch: MagicMock, mock_incr: MagicMock
+        self, mock_trigger: MagicMock, mock_fetch: MagicMock, mock_incr: MagicMock
     ) -> None:
         mock_fetch.return_value = self.group_event.occurrence
 
@@ -901,6 +912,7 @@ def test_metrics_issue_dual_processing_metrics(
             },
             sample_rate=1.0,
         )
+        mock_trigger.assert_called_once()
 
     def test_basic__no_filter(self) -> None:
         triggered_action_filters, _ = evaluate_workflows_action_filters(