Patio door lock
I've never heard from any of our customers that they experienced a problem with the hook falling. Could you send us a picture of what you're using now and possibly showing the problem that you're having? Thank you!
Well, I can tell you that this looks like our 82-226 lock. However I'm not 100% sure what the issue is. Your first post is a little unclear. I would try this: install the lock you got from Menards as normal. Then, remove your handle set from the door entirely. Try turning the lock manually using a flat head screwdriver. If the problem persists, then it's definitely the mortise lock that broke. It seems unlikely to me that Menards would sell you a defective lock with an identical problem to your old lock, but stranger things have happened.
However if the mortise lock works fine then there's a problem somewhere else. Let me know and we can cross that bridge when we get there.