Hi
Disclaimer:
The following is not an everyday occurrence just once in a great while 😂
This is not a hardware/software solution more aptly it’s a “try-it” to see if corrects the lip sync issue. It more so involves AV cable/stream viewing.
After adjusting the Lip Sync in the Sonos app and still no Joy. Stop the AV stream either by turning the TV off or temporarily switching to another stream. I’ve found it fixes the issue 100% of the time when the Sonos app lip sync adjustment doesn’t correct the issue to my liking. I guess it resets the stream so to speak. So give it a try.. you have nothing to lose kind’a 😊
Note:
You will most likely miss a portion of the AV Stream unless you can time shift to recover the missed portion.