Try connecting the Switch to a different HDMI port. Also try using a different HDMI cable with the Switch. If that doesn’t work, disconnect the Apple TV and Xbox and see if it makes any difference.

I swapped my Apple TV and Switch and, while it seemingly fixed the Switch, it now results in dropouts on 5.1 content from my Apple TV. (But Atmos content seems fine, so it's something with 5.1 specifically) So something is clearly wrong with the way 5.1 is processed from ports that aren't the first that's broken somewhere.

Am I out of luck if I want all of my components to work properly? Switching cables around all the time is both a hassle and resets all my picture settings.

Could there be an issue with the HDMI 3 port? If you connect the Xbox to HDMI 3, do you have issues? How does the Apple TV do connected to HDMI 4?

Swapped the Switch to HDMI 4 and still got dropouts. Which seems to tell me the problem is something in the processing chain of those two ports specifically for 5.1.

Try this:

Leave HDMI 1 and 4 open. Test each device individually on HDMI 3.

Both have dropouts on HDMI 3 when 1 and 4 are empty (this did not surprise me given the results of all the past tests…).

Are the ports on this model just busted? Can I just not use 5.1 on whatever I put into ports 3 or likely 4 without dealing with this issue?

Surely it isn't a bandwidth concern considering I had earlier tested Atmos on the Apple TV on that port and it seemed fine.

Try one more thing:

Disconnect everything from the TV and unplug the Beam and TV from power for a couple of minutes. Plug everything back in but keep everything disconnected. Make sure Simplink is enabled in the TV settings. Run TV Setup in the Sonos app and follow the app instructions. When the app instructs you, connect the Beam to the TV’s HDMI ARC/eARC port using the Sonos-supplied HDMI cable. After the Beam has been successfully connected, connect your other devices to the TV.

Just did all of that and still got a dropout on the Switch after a few minutes :/

Not sure what else to do other than getting an HDMI switch and connecting all three devices to HDMI 1 through the switch.

Surely that would introduce some input lag (and likely break CEC auto switching) yes?

Frustrating that the only “solution” would be to use some extra box as a workaround

You could wait for the problem, submit a diagnostic and contact Sonos support so they can look at the internal data we users can’t see. Maybe it will show another option.

I had this problem show up out of nowhere yesterday. Exactly every minute, the sound from the Nintendo Switch would cut out for exactly a second.

I fixed it with these steps:

1. Unplug every HDMI cable from my LG CX, including ones unrelated to the Nintendo Switch or Beam.
2. Unplug the power to the TV, waiting 10 seconds
3. Plug the TV power back in and wait for it to boot up and show the “No Signal” screensaver.
4. One by one, plug each HDMI cable back into the TV, and wait for each one to register and show an input signal (except Sonos Beam, since it’s just ARC). Go too fast and the inputs might get jumbled up, so be extremely patient, and don’t plug in multiple cables at once.

After that, the sound came through uninterrupted for the rest of the night.