Hi @Glemay75, welcome to the Sonos Community! I appreciate you reaching out here and I’d be happy to assist you. Do you have other devices connected to the TV aside from the Sonos Amp? If yes, try to disconnect them all and just leave Sonos Amp connected. Also, if you have another TV where you can try it to isolate or try an optical audio adapter. Have you also consulted Sony about this as it could be something to do with the TV on how it handles it? 

Keep us posted here. We and the community are always here to help.

I had the same problem with my AF8 connecting to Sonos Arc. I set the audio to internal and few seconds later it will auto switch to external (ARC). Disabling the Bravia Sync will result in no audio sent to Arc at all. 

I dont experience this previously when connecting my sony TV to Denon AVR.