I've made some changes to my rig recently. I'm running a 6505+, a G Major and a Ground Control MIDI board. I'm using the FJA 6505+ to G Major cable which enables channel switching via the relays of the G Major (or something to that effect).
The Issue: The amp channels switch by themselves maybe after 20-30 seconds of staying on one patch. The G Major patch stays the same while the amp channels switch from dirty to clean by themselves.
Example- I'm on a Dirty Channel with Delay. A few seconds later the amp will switch to Clean while the G Major keeps the Delay. If I go back to the tone patch all will be fine until it does it again.
I'm dumb, helpz.
Don't quote me on it, but I think Peavey uses momentary, not latching switches. Try changing the switch type in the GMajor and see if the problem goes away.