I'm using a 1st gen AppleTV 4k along with a sofabaton U1 as a bluetooth remote, and sound through a connected AV amp.
When I use other apps, the mute / volume up & down interact as you would expect - after muting sound, I can press any of the mute, volume up or volume down buttons and the sound unmutes properly.
The channels app behaves differently - it appears to be keeping track of the mute state in the app seperate to the device state, and can get out of sync with the device.
After muting channels, I can unmute normall by pressing the mute button.
If instead of this I unmute by pressing volume up or down, the apple tv unmutes and sends the signal to the AV amp to unmute, but the channels app stays muted (continues to show the on screen mute icon) and I get no sound. Once in this state, pressing mute again will toggle the mute state on both the channels app and the device, which means they continue to remain out of sync and there is no sound.
The only way to get them back in sync is to toggle the mute so that the channels app thinks it is unmuted but the amp is still muted, then press volume up or down again.
This behaviour is not seen with any other app on the AppleTV, only channels. The sofabaton is defintely not talking direct to the AMP - it is only programmed to operate the AppleTV
Anybody else seen similar? Have I missed a setting somewhere or is this a known issue?