Hello, I'm posting this here as well as contacting Sony support. Basically the Android 9 update has broken audio output on my XG9505. The issues are the same with two different soundbars (a Cambridge Audio, and Sony HT-Z9F). Before the update audio was 99% stable.

Symptoms since the update:

• Loss of sound using built in Netflix & YouTube. 50% of the time audio will not work when starting something. Sometimes it can be fixed by switching to another source and back again, but usually requires putting the TV into standby. One time I switched to TV speakers after it happened and there was no sound through them either. Amazon Prime appears unaffected.
• Occasional loss of sound on devices connected via HDMI to the TV including a Sony bluray player and PS4 Pro. This can be 1 hour+ into use. Toggling to TV speakers and back usually fixes.
• With "Digital Audio Out" set to "Auto 1", Broadcast (satellite) HD channels work, but if you switch from a HD to SD channel there will be no sound on any SD channels until you toggle to TV speakers and back or put into standby. "Auto 2" is working so far but is lower quality on stereo sources.
• Also with "Auto 1" & "Auto 2" on switching to a HD channel the audio will drop out briefly after a few seconds. On BBC channels this is about the same time as the red button banner appears.

Things I've tried:

• Factory reset. For about 2 hours after the reset everything worked flawlessly, then all the problems suddenly returned.
• Changing HDMI cables, and making sure they're "high speed".
• Turning off e-ARC.
• "Digital Audio Out" set to "PCM". Fixes broadcast TV problem like "Auto 2" but doesn't help other issues.

It's making it very difficult to use the TV now, especially for the non-techy family members. Can anyone advise on other things I can try?

On the old firmware I only experienced audio loss a handful of times in 6 months, is there a way to roll back to that?

There are multiple posts about the issue on various forums, but so far there doesn't seem to have been any official recognition from Sony?

As a last resort I could get a streaming stick to replace the apps, but everything was working great on Android 8 and I'd like to have the same experience, plus it is occasionally affecting attached devices too.

Thanks in advance for any help you can provide.