It’s mapped directly to the expression pedal, not very fancy, really.
I wonder if you’re getting some jitter from your expression pedal. Not sure that the exact model of EXP pedal will help here. I’ve seen jitter in many of them. If you can tighten up the treadle, that can help in some cases (mechanical movement – not values jittering from potentiometer slop).
One way to test (easier in H90 Control) would be to open up the expression pedal mapping on any parameter, dial in the low & high ranges, then leave that popup window open for a while. Don’t touch the EXP pedal, and see if the mapping changes.
I guess another way would be to set up the saved EXP pedal positions in both Program #1 and Program #2. Unplug the EXP pedal from the H90. Then switch between Program #1 & #2, and see if the behavior persists.
