Welcome to Android Central! I think that "mob" means "mobile phone." Are you saying that when you're in an app, it'll briefly exit to the homescreen, then switch back to the app? Does this happen with any app, or only certain ones?
I posted yesterday regarding when i'm on facebook and my mobile phone (one plus 6t) is switching for a few seconds to home screen and comes back to the posts i was viewing on facebook. Its been doing this these last three days, i didn't had any issues before. What could be the reason ?
Welcome to the forums. We get lots or reports about different Facebook bugs and usually they are caused because the app is just bad. You could try changing the way Facebook open links and see if it makes any difference. See this thread.