Apple Music on Apple TV 4K it only plays mono

The Apple TV will only play mono when using Apple Music.

All other apps work fine and out Dolby 5.1, etc

I have checked accessibility and it is not set to Mono

I have checked the Apple Music App and it is set to Lossless

Apple TV software is up to date, the AV processor I am using is fairly high-end (Anthem AV-70) - so I know it is not a downstream issue, since all the other apps on the Apple TV will pass multi-channel signals which the Anthem can process.

Funny thing is it used to work just fine but about a year or two ago it only plays mono.

Thank you