diff --git a/openedx/core/djangoapps/config_model_utils/models.py b/openedx/core/djangoapps/config_model_utils/models.py
index 5a46541a93..466baddf03 100644
--- a/openedx/core/djangoapps/config_model_utils/models.py
+++ b/openedx/core/djangoapps/config_model_utils/models.py
@@ -183,19 +183,20 @@ class StackedConfigurationModel(ConfigurationModel):
 
         values = field_defaults.copy()
 
-        global_override_q = Q(site=None, org=None, org_course=None, course_id=None)
-        site_override_q = Q(site=site, org=None, org_course=None, course_id=None)
-        org_override_q = Q(site=None, org=org, org_course=None, course_id=None)
-        org_course_override_q = Q(site=None, org=None, org_course=org_course, course_id=None)
-        course_override_q = Q(site=None, org=None, org_course=None, course_id=course_key)
+        # Build a multi_filter_query that defaults to querying for the global-level setting and adds queries
+        # for the stacked-level settings when applicable.
+        # Note: Django2+ requires checking for 'isnull' rather than passing 'None' in the queries.
+        multi_filter_query = Q(site__isnull=True, org__isnull=True, org_course__isnull=True, course_id__isnull=True)
+        if site:
+            multi_filter_query |= Q(site=site, org__isnull=True, org_course__isnull=True, course_id__isnull=True)
+        if org:
+            multi_filter_query |= Q(site__isnull=True, org=org, org_course__isnull=True, course_id__isnull=True)
+        if org_course:
+            multi_filter_query |= Q(site__isnull=True, org__isnull=True, org_course=org_course, course_id__isnull=True)
+        if course_key:
+            multi_filter_query |= Q(site__isnull=True, org__isnull=True, org_course__isnull=True, course_id=course_key)
 
-        overrides = cls.objects.current_set().filter(
-            global_override_q |
-            site_override_q |
-            org_override_q |
-            org_course_override_q |
-            course_override_q
-        )
+        overrides = cls.objects.current_set().filter(multi_filter_query)
 
         provenances = defaultdict(lambda: Provenance.default)
         # We are sorting in python to avoid doing a filesort in the database for