The distance between it and the Beam makes no difference, it would only make a difference if it was ‘bonded’ as a surround speaker. When grouped, all data comes from your router, unless you’re using SonosNet.
The TV data is a larger bandwidth signal than most music streams, much like all line in signals. It suggests that there is some level of wifi interference that is impacting that speaker.
But, this is a guess. Given the lack of information in your post, perhaps it might be best if you were to submit a system diagnostic within 10 minutes of experiencing this problem, 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.
