diff --git a/lms/djangoapps/grades/signals/handlers.py b/lms/djangoapps/grades/signals/handlers.py
index 03176632b94..950c7f017df 100644
--- a/lms/djangoapps/grades/signals/handlers.py
+++ b/lms/djangoapps/grades/signals/handlers.py
@@ -152,7 +152,7 @@ def score_published_handler(sender, block, user, raw_earned, raw_possible, only_
         if previous_score is not None:
             prev_raw_earned, prev_raw_possible = (previous_score.grade, previous_score.max_grade)
 
-            if not is_score_higher_or_equal(prev_raw_earned, prev_raw_possible, raw_earned, raw_possible):
+            if not is_score_higher_or_equal(prev_raw_earned, prev_raw_possible, raw_earned, raw_possible, True):
                 update_score = False
                 log.warning(
                     "Grades: Rescore is not higher than previous: "
diff --git a/openedx/core/lib/grade_utils.py b/openedx/core/lib/grade_utils.py
index 2e7073e962d..48c262e85a5 100644
--- a/openedx/core/lib/grade_utils.py
+++ b/openedx/core/lib/grade_utils.py
@@ -17,14 +17,14 @@ def compare_scores(earned1, possible1, earned2, possible2, treat_undefined_as_ze
     """
     try:
         percentage1 = float(earned1) / float(possible1)
-    except ZeroDivisionError:
+    except (ZeroDivisionError, TypeError):
         if not treat_undefined_as_zero:
             raise
         percentage1 = 0.0
 
     try:
         percentage2 = float(earned2) / float(possible2)
-    except ZeroDivisionError:
+    except (ZeroDivisionError, TypeError):
         if not treat_undefined_as_zero:
             raise
         percentage2 = 0.0