Setup:  This situation can happen but it's not clear how to trigger it so we will change the database to make it happen and test this issue. 1. Edit "mod/scorm/lib.php" 2. In the scorm_delete_instance() function move the call to "scorm_grade_item_delete()" to the end of the function 3. Create a course with two assignment activities and some students.  5. Make sure the admin setting "debugdisplay" is turned on 6. Make sure the admin setting "debug" is set to "Developer..." 7. Run this query in the database: "delete from mdl_course_modules where module = (select id from mdl_modules where name = 'assign');" 8. Purge all caches Test: 9. Access the gradebook "Setup" for the course 10. Delete the first assignment activity 11. Verify you see "Can not find assign activity with id 1" messages on the "redirect" page (can be multiple times) 12. Make sure the admin setting debugdisplay is turned off 13. Access the gradebook "Setup" for the course 14. Delete the second assignment activity 15. Verify you do not see any error messages