Audio not in sync with picture

I have my sound running through my JBL surroundsound system approximately 10 days ago the audio started falling to sync with the picture.

Xfinity recommended I update my box which I did and the issue is still persistent what has changed on Xfinity‘s end? Line cables are tight I can stream video and the audio is in sync which points to Xfinity box issue please help can’t have TV like this