diff --git a/db/migrations/5.1.4_fix_my_courses_group_config.php b/db/migrations/5.1.4_fix_my_courses_group_config.php
index 7c7ab5f6c7f8210610f8a9292197507366c8a2c5..a7a972cb74e90fc68c51ec1779871cccf1069446 100644
--- a/db/migrations/5.1.4_fix_my_courses_group_config.php
+++ b/db/migrations/5.1.4_fix_my_courses_group_config.php
@@ -23,7 +23,7 @@ final class FixMyCoursesGroupConfig extends Migration
                 }
 
                 if ($changed) {
-                    $value->value = json_encode($groups);
+                    $value->value = json_encode(array_values($groups));
                     $value->store();
                 }
             },