I won't be able to get this information until my next rehearsal this coming Saturday (7/29). Quite a while back, I can't remember the date, you sent me a set of replacement switches that have been working perfectly. I don't think this is a HW (physical switch) issue, as I can reproduce the issue with at least two different switches on the unit. FWIW, the button boards are REV2 (PCB-MMGTB1 REV2).
I will also update to 3.4.8 (from 3.4.7) this Saturday (7/29) and see if that addresses the issue.
Switches: 000000
When I tried to load the 3.4.8 firmware, the MMGT gets stuck in a loop saying "Unable to open directory."
I tried two different thumb drives and got the same results.