i am having the same problem since 9.0.5. The "volume pedal" meter randomly drops from 127 to between 5 & 20 resulting in most if not all signal being cut. When I return it to 127, it will drop out again after a period of time.
However this ONLY happens to me when my MIDI controller (RJM PBC/10) is plugged in. I checked to make sure I was not sending any accidental CC or otherwise messages to it, and as I thought, it wasn't. When I unplug MIDI, everything stays put as it should.
A good bit of info though is that this past few days I was playing shows in Vienna, VA/Hampton, VA/ & NYC - 3 separate days, 3 separate locations/3 separate KPAs backlined with OS 9.0.5 - all of them behaved the exact same which resulted in me unplugging my midi from my pedalboard to kemper and playing through one out of the 3 sounds i use with this artist.
i should note this is in performance mode AND browser mode.
to confirm - Exp inputs are set to OFF, and nothing is plugged into them.