While I don’t have an Arc Ultra, both my Arcs play what they’re handed by their respective TV sets. When they don’t, it’s due to the TV not providing them a signal to play.
I’d be checking for firmware/software updates to your TV, then talking to Sky about the sound dropping when you pause play back.
Thanks Bruce….this was never an issue with the my PlayBar and has only started I since upgraded the Arc Ultra…same TV same Sky Box.