Keep markers at the track if child_at_time() found something that does not hold markers

contrib/opentimelineio_contrib/adapters/advanced_authoring_format.py

@@ -1247,7 +1247,7 @@ def _attach_markers(collection):
 
                 # determine new item to attach the marker to
                 target_item = target_track.child_at_time(marker.marked_range.start_time)
-                if target_item is None:
+                if target_item is None or not hasattr(target_item, 'markers'):
                     target_item = target_track
 
                 # attach marker to target item

contrib/opentimelineio_contrib/adapters/tests/test_aaf_adapter.py

@@ -215,6 +215,11 @@
     "keyframed_properties.aaf"
 )
 
+MARKER_OVER_TRANSITION_PATH = os.path.join(
+    SAMPLE_DATA_DIR,
+    "marker-over-transition.aaf",
+)
+
 
 def safe_str(maybe_str):
     """To help with testing between python 2 and 3, this function attempts to
@@ -1100,6 +1105,26 @@ def test_aaf_transcribe_log(self):
         self.assertEqual(result_stdout, TRANSCRIPTION_RESULT)
         self.assertEqual(result_stderr, '')
 
+    def test_aaf_marker_over_transition(self):
+        """
+        Make sure we can transcibe this composition with markers over transition.
+        """
+
+        timeline = None
+
+        try:
+            timeline = otio.adapters.read_from_file(
+                MARKER_OVER_TRANSITION_PATH
+            )
+
+        except Exception as e:
+            print('[ERROR] Transcribing test sample data `{}` caused an exception: {}'.format(
+                os.path.basename(MARKER_OVER_TRANSITION_PATH),
+                e)
+            )
+
+        self.assertIsNotNone(timeline)
+
     def _verify_user_comments(self, aaf_metadata, expected_md):
 
         self.assertTrue(aaf_metadata is not None)