diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index a0ad22cd..bf5930c2 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -36,6 +36,7 @@ jobs:
         shell: bash
         env:
           _MERGIFY_TEST_NEW_FLAKY_DETECTION: "true"
+          MERGIFY_TEST_FLAKY_DETECTION: "true"
           PYTHONUTF8: "${{ matrix.os == 'windows-2025' && 1 || 0 }}"
         run: poetry run poe test
 
diff --git a/mergify_cli/tests/ci/test_junit.py b/mergify_cli/tests/ci/test_junit.py
index d3dd5e2d..a9c7684c 100644
--- a/mergify_cli/tests/ci/test_junit.py
+++ b/mergify_cli/tests/ci/test_junit.py
@@ -535,6 +535,7 @@ async def test_traceparent_injection(
         "00-80e1afed08e019fc1110464cfa66635c-7a085853722dc6d2-01",
     )
     monkeypatch.setenv("_MERGIFY_TEST_JOB_NAME", "foobar")
+    monkeypatch.delenv("MERGIFY_TEST_FLAKY_DETECTION", raising=False)
     filename = pathlib.Path(__file__).parent / "junit_example.xml"
     run_id = (32312).to_bytes(8, "big").hex()
     spans = await junit.junit_to_spans(