Can you please share the course URL, name of the quiz where the issue is appearing and admin credentials as well as a valid FTP credential of your new testing site to check the issue at your end.
PS: mark reply as private while sharing.
This reply has been marked as private.
Ok I think we have got to the bottom of the problem. It was a depreciated RESULTS.php page template used in the Child Theme. Removed this and yeap fixed the problem. Closed from our point of view.