That sure seems like a case of wifi interference of some kind, leaking in to the Beam. The next time it happens, submit a system diagnostic within 10 minutes, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.

Does the sound still occur if you remove the HDMI cable from the TV? - I assume you are using the Arc connection, rather than the Optical adapter? If the issue stops, then perhaps next go onto try a different HDMI cable that is 1.4+ compatible (with HEAC support), which you will know just from the fact the TV sound will still work.

If the problem returns, then it might be an issue with the TV perhaps, or one if it’s other connected devices, but try powering that off for a good three minutes or so to drain all power from its circuits and remove anything else connected to its ports and then try it again with just the Beam attached.

Unfortunately I’m continuing to get interference on my sound bar. Diagnostics report number is 548599402. Can someone please investigate? Thank you 

I would perhaps contact Sonos Support Staff using the link provided in @Airgetlam’s post above. They will need to review your diagnostic report and you can perhaps explain in detail what interference you are experiencing with your Beam.