diff --git a/lms/djangoapps/grades/tasks.py b/lms/djangoapps/grades/tasks.py
index 88384cf6e5..d213ec46e2 100644
--- a/lms/djangoapps/grades/tasks.py
+++ b/lms/djangoapps/grades/tasks.py
@@ -135,6 +135,9 @@ def _has_database_updated_with_new_score(
                 "item_type": "openassessment"
             }
         )
+        if api_score is None:
+            # Same case as the initial 'if' above, for submissions-specific scores
+            return score_deleted
         reported_modified_time = api_score.created_at
     else:
         reported_modified_time = score.modified