Well, I’d say re-download the app anyway. I mean, why not? That takes like 30 seconds and eliminates that possibility.
But if that doesn’t fix it then I’d say #3 is probably most likely. This really shouldn’t be happening. If it is, it’s an indication that something is pretty wrong with the operating system at a pretty fundamental level.
If my mac was doing this (and yes, it has done similar things) I’d double check my backups are up-to-date and working well, then format the drive. I wouldn’t even wait a minute.
If that’s too daunting, I’d really consider having a professional look at it. But, yeah, re-download the app first thing.