Input from the TV tends to be ‘denser’ than normal music streams, which means the connection between the two requires more bandwidth, and is more susceptible to  wifi interference. You may want to check for potentials in that linked FAQ. 

However, if that doesn’t resolve the intermittent dropouts, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. But don’t post the resulting diagnostic number here, they get sensitive about GDPR.

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 Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.