Known (I think).
I’m aware of this, and (sigh) it’s on my list.
This bug is driving me crazy. Android… pfft 
Might be a pixel shader issue. Will investigate.
That was intentional, but I think I got confused by the (Microsoft) requirement that apps shouldn’t have quit buttons. So it will be changed.
This is poorly worded. The problem was that pressing back on the main menu would cause the app to terminate. The correct way to solve this is not to make the main menu unquittable, but make it that the back button puts the app in the background (but it still runs when you return to it).
The closest I have is a Galaxy A5 (2016). I’ll see if it has the same problem.
Agreed. I don’t see how this can possibly be fixed, though.