係Av forum 睇到一個外國人問Sony
I got answer from our Sony Russia support
Google translated:
Thank you for your long wait!
The indicated symptom of cut sound with tv and some soundbar models was reproduced by our engineers with both the previous and the new version of the firmware. At present, the causes and remedies are being investigated, which, we hope, will already be applied in the next versions of the software for TV and / or soundbar.
Temporary disabling of Bluetooth and eARC may help at a specific moment.
希望下次update有改善