diff --git a/src/openforms/config/tests/factories.py b/src/openforms/config/tests/factories.py
index 08476e714b..745819c796 100644
--- a/src/openforms/config/tests/factories.py
+++ b/src/openforms/config/tests/factories.py
@@ -17,7 +17,7 @@ class Meta:
 
 
 class MapTileLayerFactory(factory.django.DjangoModelFactory):
-    identifier = factory.Faker("word")
+    identifier = factory.Sequence(lambda n: f"map-tile-layer-{n}")
     url = factory.Sequence(lambda n: f"http://example-{n}.com")
     label = factory.Faker("word")
 
diff --git a/src/openforms/submissions/tests/test_post_submission_event.py b/src/openforms/submissions/tests/test_post_submission_event.py
index e4a975d28b..739c9a0712 100644
--- a/src/openforms/submissions/tests/test_post_submission_event.py
+++ b/src/openforms/submissions/tests/test_post_submission_event.py
@@ -15,12 +15,14 @@
 from openforms.emails.tests.factories import ConfirmationEmailTemplateFactory
 from openforms.forms.constants import LogicActionTypes, PropertyTypes
 from openforms.forms.tests.factories import FormLogicFactory
+from openforms.logging.models import TimelineLogProxy
 from openforms.payments.constants import PaymentStatus
 from openforms.payments.tests.factories import SubmissionPaymentFactory
 from openforms.registrations.base import PreRegistrationResult
 from openforms.registrations.contrib.zgw_apis.tests.factories import (
     ZGWApiGroupConfigFactory,
 )
+from openforms.tests.utils import log_flaky
 from openforms.utils.tests.logging import ensure_logger_level
 
 from ..constants import PostSubmissionEvents, RegistrationStatuses
@@ -893,8 +895,24 @@ def test_cosign_not_required_and_not_filled_in_proceeds_with_registration(self):
         mock_payment_status_update.assert_not_called()
 
         mails = mail.outbox
+        submission.refresh_from_db()
+
+        # FLAKINESS HERE happens something, try to figure out what's going wrong
+        if not mails:
+            log_flaky()
+
+            # try to detect why no registration email was sent
+            print(f"{submission.registration_status=}")
+            print(f"{submission.payment_required=}")
+            print(f"{submission.confirmation_email_sent=}")
+            print(f"{submission.form.send_confirmation_email=}")
+            # and print logevents
+            logs = TimelineLogProxy.objects.for_object(submission)
+            for log in logs:
+                print(log.message().strip())
+
+        self.assertEqual(len(mails), 1)  # No cosign request email!
 
-        self.assertEqual(1, len(mails))  # No cosign request email!
         self.assertEqual(
             mails[0].subject, "Confirmation of your Pretty Form submission"
         )
@@ -905,8 +923,6 @@ def test_cosign_not_required_and_not_filled_in_proceeds_with_registration(self):
 
         self.assertNotIn(cosign_info, mails[0].body.strip("\n"))
 
-        submission.refresh_from_db()
-
         self.assertFalse(submission.cosign_request_email_sent)
         self.assertTrue(submission.confirmation_email_sent)
         self.assertNotEqual(submission.auth_info.value, "111222333")