I have a friend (yes. That's a real friend. It wasn't me secretly), and his account seemed to get hacked earlier this morning. He got completely shut out, couldn't even log in. Messenger too. So he tries to make a new one. It lasts a little while but then that shuts him out as well. He tries one last time for a new one and finally he gets one that lasts.....until the evening when this third one gets shut down as well. He tries to report it, but the site isnt allowing his phone number as security - keeps saying its invalid. He doesn't know what to do, until a few minutes later. His original account is suddenly back. He can log in fine and everything, it seems, is weirdly back to normal. It's also strange that hes seen it before, years ago with one of his friends. If anyone has an explanation for this weird course of events, please do let me know.
It's possible that their filters detected a suspicious activity and the original account got flagged. Then a real human took a look and got it unsuspended. As far as his other accounts, since FB doesn't allow multiple personal accounts the moment they got connected (possibly by IPs) they got disabled.
Account is not hacked. Its a facebook issue. Happens to me often. I think it happens when facebook is modifying some code in the backend or something. Generally when it happens, after that I see a minor change in their app functionality here and there. This is why I think that it happens when fb is changing their code.