Audio goes to to constant 'BUZZ/BLARING' noise

I use an ATV4 and an ATV4K clients that in the past 3 days will randomly go to a very loud BUZZING/BLARING several decibels louder than the audio when using Channels DVR and watching a recording. The ATV4 wouldn't clear the issue until 'restarted' from 'settings', the ATV4K has done it twice today and the depress of the ON/OFF then OFF seemed to clear it. tvOS is 17.6.1

Both systems are HDMI to Yamaha receiver then to TV using Boston speakers 5.1.

I've had ATV4 & 4K with these same receivers and TV for 3 plus years. Any thoughts?