Bose S1 Pro + signal drop off

I have 4 S1 Pro + and all of them are doing the same thing. It seems there is a signal/volume drop that randomly happens.
A perfect example: Playing a guitar Chord the sustain drops off… cuts off mid sustain.
Vocals are randomly dropping in volume.
All the S1 Pro + have the firmware update.
I am plugged in direct, I am not using wireless, and have tried different mics and guitars and the same thing happens.
It happens with plug in power and also on battery.
Any help would be appreciated.