Ok, good to know. If it happened to you it would be very obvious. It goes downhill and leaves you barely able to do anything because the screen refreshes so slowly. You're still "there", but it's like watching in extreme slow motion. Then if you die it clears up immediately.

I believe there's some memory leak or something that just takes a while to build up and slow down the app's processing to the point that it starts missing screen updates. If you don't see it on Android 4.3 then it means it's device-specific somehow. Although I can't remember exactly the time, 10 minutes might be right on the border. If you ever do 20+ mins and don't see the problem, then that's pretty strong proof.