Agreed that this is really annoying. It happens on Now TV sports channels (mainly football) on my BT 4K box but doesn't seem to happen when viewing on demand entertainment (like box sets).
It seems worse at weekends when it regularly just stops, probably a message size / buffering issue error due to higher demand.
@palmeri8145 are you watching sports live through the NowTV app or catch up content??
If you're watching live, why not watch through the Youview EPG as they're broadcast via the multicast system so you won't have any buffering at all.
I've got the same problem freezing stuffing with on-demand programs and films what I done is I went into the NOW TV app and into account and I went to the NOW TV booster and put it into Sony surround and it worked no picture broke up the only works for the entertainment programs like games of throne they doesn't work with the movies still break the movie still pleases and Buffon if I put it back into stereo it takes up again and freezers and buffers