I am running channels on firestick 4k and sometimes my DVR recording picture will freeze and I have to open and close the app a few times to get it to go back to main screen. U can usually still hear the audio still when the screen freezes. I have not had issues on iPad but I also don't use it as much as firstick so maybe it just had not happened yet.
Was watching show yesterday and had no issues, started the next show I had and it freeze multiple times I ended up just finishing it on iPad with no issues.