diff --git a/mod/assign/locallib.php b/mod/assign/locallib.php
index 8ed73e8a1f7..31f37f1bb6b 100644
--- a/mod/assign/locallib.php
+++ b/mod/assign/locallib.php
@@ -9858,7 +9858,7 @@ function move_group_override($id, $move, $assignid) {
     global $DB;
 
     // Get the override object.
-    if (!$override = $DB->get_record('assign_overrides', ['id' => $id], 'id, sortorder, groupid')) {
+    if (!$override = $DB->get_record('assign_overrides', ['id' => $id, 'assignid' => $assignid], 'id, sortorder, groupid')) {
         return false;
     }
     // Count the number of group overrides.
@@ -9887,8 +9887,8 @@ function move_group_override($id, $move, $assignid) {
 
         // Delete cache for the 2 records we updated above.
         $cache = cache::make('mod_assign', 'overrides');
-        $cache->delete("{$override->assignid}_g_{$override->groupid}");
-        $cache->delete("{$swapoverride->assignid}_g_{$swapoverride->groupid}");
+        $cache->delete("{$assignid}_g_{$override->groupid}");
+        $cache->delete("{$assignid}_g_{$swapoverride->groupid}");
     }
 
     reorder_group_overrides($assignid);