Hi @MrDeps.
Thanks for reaching out and welcome to the community! Let me see what I can do to help you.
If your TV has an HDMI ARC port, you have to connect the Beam’s HDMI cable directly to the TV’s HDMI ARC port and not on eARC.
Currently, Arc is the only Sonos product compatible with the eARC connection.
We also need to ensure that ARC is enabled on the TV, some TVs that support ARC have a menu setting to enable or disable it, you may check/consult it with the manufacturer support page or TV manual.
If your TV doesn’t have an HDMI ARC port, you can attach the optical adapter to the Beam’s HDMI cable and connect it to the TV’s optical digital OUT port.
For more details, you may see this article that describes some basic requirements when using Sonos speakers on your TV.
Some streaming service content (such as Netflix or Vudu) is streamed with Dolby Digital Plus (DD+) surround audio, which is only supported by Sonos Arc. Is Netflix a built-in app on the TV? I suggest that you try changing your device’s audio output to a supported audio format.
If the above advice was followed and the issue persists, kindly reproduce the issue then submit a diagnostic report through the Sonos app shortly when it happens, and reply with the confirmation number, I'd start by reviewing your system and see if there’s anything causing this issue.
Let me know how that goes.