Whilst watching pretty much any app, definitely including Amazon Prime and also YouTube, the picture will occasionally freeze but the sound continues to play. After trying many things, the best work around I’ve found is to skip backwards a few minutes or so
(long enough to ensure it’s not in the range that’s buffered) and force it to rebuffer the video. It then continues past the previous point of failure, often to happen again later on.
This is quite a frequent occurrence. For example, it’s happened 3 times so far on this one 27 minute YouTube video. At other times it can play all evening without this occuring once.