Does this happen at home as well?

I ask because one of the things that can cause the rotary control to appear to misbehave is sending dimmer commands to the display board - the same PIC does the rotary control and dimmer contblrol. If you had a lights-on sense like that was wobbling a bit, it would cause brightness change commands to be sent to the front panel (even if the brightness setting was the same, I think) and that may well upset the rotary control code.

Hugo