diff --git a/cms/djangoapps/models/settings/course_grading.py b/cms/djangoapps/models/settings/course_grading.py
index 3d0b8f78af..f1f68b5f5b 100644
--- a/cms/djangoapps/models/settings/course_grading.py
+++ b/cms/djangoapps/models/settings/course_grading.py
@@ -118,6 +118,8 @@ class CourseGradingModel(object):
             descriptor.raw_grader[index] = grader
         else:
             descriptor.raw_grader.append(grader)
+        # make definition notice the update
+        descriptor.raw_grader = descriptor.raw_grader
 
         get_modulestore(course_location).update_item(course_location, descriptor.definition['data'])