Without any identifiable cause, Mathematica will occasionally seem to remap keyboard shortcut keys and menu items. I typically notice this with Ctrl-S, which I use often to save. All of a sudden, it will no longer save, but will do some other (usually undesirable) action. The action changes on each instance of the bug.
This problem has been driving me nuts, and has been happening maybe once a week for a year or two now. For the record, I'm on version 12.0.
Just now, for example, Ctrl-S decided to change my stylesheet to some Report format. Choosing Save from the menu had the same result. This isn't a case of having Caps Lock on by mistake or anything.
This problem sometimes resolves on its own, or if I mash on my keyboard in frustration (really, that does sometimes fix it -- I assume it has to do with the alt/ctrl/etc modifiers getting into a bugged state), but is always fixed by closing and restarting Mathematica.
Is this a known issue? Is there a fix? Thanks!