Had my first gig with my HD500x recently. Sometimes when I'd press the expression pedal toe switch, my tone's volume would switch to the level the volume knob was currently set to, which was quite annoying. I tested this yesterday and it does keep happening (sometimes, though very rarely, if I just mess with the pedal in general) from time to time. The display briefly shows the amp settings screen as if I had physically nudged the tone volume knob.
Is this something that's happened to anyone or should I just take it in to get it repaired?