diff --git a/pymongo/_client_bulk_shared.py b/pymongo/_client_bulk_shared.py
index 4dd1af2108..649f1c6aa0 100644
--- a/pymongo/_client_bulk_shared.py
+++ b/pymongo/_client_bulk_shared.py
@@ -74,4 +74,6 @@ def _throw_client_bulk_write_exception(
                 "to your connection string."
             )
             raise OperationFailure(errmsg, code, full_result)
+    if isinstance(full_result["error"], BaseException):
+        raise ClientBulkWriteException(full_result, verbose_results) from full_result["error"]
     raise ClientBulkWriteException(full_result, verbose_results)
diff --git a/pyproject.toml b/pyproject.toml
index 8452bfe956..225be8e1d8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -74,6 +74,7 @@ addopts = ["-ra", "--strict-config", "--strict-markers", "--junitxml=xunit-resul
 testpaths = ["test"]
 log_cli_level = "INFO"
 faulthandler_timeout = 1500
+asyncio_default_fixture_loop_scope = "session"
 xfail_strict = true
 filterwarnings = [
     "error",
diff --git a/test/asynchronous/conftest.py b/test/asynchronous/conftest.py
index e443dff6c0..c08f224abd 100644
--- a/test/asynchronous/conftest.py
+++ b/test/asynchronous/conftest.py
@@ -17,6 +17,8 @@ def event_loop_policy():
     # has issues with sharing sockets across loops (https://github.com/python/cpython/issues/122240)
     # We explicitly use a different loop implementation here to prevent that issue
     if sys.platform == "win32":
+        # Needed for Python 3.8.
+        asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
         return asyncio.WindowsSelectorEventLoopPolicy()  # type: ignore[attr-defined]
 
     return asyncio.get_event_loop_policy()
diff --git a/test/conftest.py b/test/conftest.py
index a3d954c7c3..ca817a5a62 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -15,6 +15,8 @@ def event_loop_policy():
     # has issues with sharing sockets across loops (https://github.com/python/cpython/issues/122240)
     # We explicitly use a different loop implementation here to prevent that issue
     if sys.platform == "win32":
+        # Needed for Python 3.8.
+        asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
         return asyncio.WindowsSelectorEventLoopPolicy()  # type: ignore[attr-defined]
 
     return asyncio.get_event_loop_policy()