Just got the Arc and have it paired with 2 Play:1’s and a gen 3 sub.
Samsung Q80R tv.
The sound from the tv will play for around 5 seconds and then cut out for around 1 second, play for 5, out for 1, on and on.
I’ve swapped out the hdmi cable twice, tried unplugging the tv, switched between PCM and DD+ and switched between different apps on the tv.
The sonos app shows that I am getting an atmos signal
Was running a beam with the Play:1’s (but no sub) before just fine.
Not sure what I should try next.
Thank you,
mike

I'm thinking of returning my Sonos ARC if the issue does not get fixed before my return window.
It is not acceptable having to disable the eARC feature permanently to avoid the bug or having to disrupt the viewing experience almost every hour to reset settings / hard reboot devices to make such an expensive soundbar work.
I'll try to contact Sonos support by phone this week to get a more precise estimate for a patch release date.
But since this thread has been going on for months, I really fear it won't be anytime soon.