It could also be the companion, but maybe it helps to find out if it is a hardware issue. You have 5 years guarantee on the upgraded amps, if you can find out which one has the issue you can send it back for repair and you can still listen with a single unit. You should at least open a ticket with Devialet support.
You can also try to use both amps in stereo mode to see if that works without issues.
Btw. I remember that I also have an issue like that very rarely. Then it seems I listen with only a single channel, in all cases the master. Then I simply switch through my 2 sources and the issue is solved. Maybe this also works for you.
You can also try to use both amps in stereo mode to see if that works without issues.
Btw. I remember that I also have an issue like that very rarely. Then it seems I listen with only a single channel, in all cases the master. Then I simply switch through my 2 sources and the issue is solved. Maybe this also works for you.