Glad to point ... have to confess, did miss mentioning the specific ones I thought might be related .. \core\task\backup_cleanup_task. Strange that you mentioned comparing your test server with production to find settings were changed upon upgrading.
But, am like you, fingers crossed that was the issue and that setting those will fix!
Now I wonder if the original poster in this thread will follow up with his system to see if this solution will provide some fixes for his.
'spirit of sharing', Ken