Are the AMP’s wireless or wired to the network? Am I correct that they are in a kitchen cabinet? Microwave ovens can cause issues for nearby wireless players.
Sometimes together can be an issue for wireless, Sonos offers options to deal with that so I’d submit a diagnostic when the issue happens again and discuss it with Sonos support.
Hi @schmooflip
Welcome to the Sonos Community!
If you are grouping in a second room to play TV audio from the first, it is expected that playback may be interrupted.
Unlike with music which can be buffered for synchronised network play, TV audio must be played immediately to stay in sync with the TV picture - this means that any speaker grouped-in does not have the advantage of a buffered audio stream.
You can improve matters by wiring both the Arc and the Kitchen Amp to ethernet, but it still relies on going through the router and so Kitchen is still likely to be a little behind Arc in playback, and uninterrupted playback cannot be guaranteed.
I hope this helps.