I've seen a few people post similar issues before, but all slightly different and haven't found a solution yet.
My EXP pedal seems to have an issue where at full heel it seldom returns to 0%, and gets worse the longer I use it. This is most apparent when using pitch whammy, where after the Helix boots up and calibrates the pedal it works perfectly fine at first, but after just a bit of use it starts to drift. Even if it goes to down to 0%, once I lift my foot it'll creep up a few %. And after just a few minutes of use it might start to settle as high as 15%, with the only fix being to reboot and let the pedal recalibrate, but it'll just go out again anyway.
This renders effects like pitch whammy completely unusable as it'll always be out of tune. I find that if I push down hard enough I can sometimes get it to go down more and even down to 0% if I really try, but it requires an unhealthy amount of force.
I have tried adjusting the tightness of the pedal, I've even pulled it apart, cleaned and relubricated the threads and washers for the EXP pedal, and while that did help a bit with the positioning and feel of the pedal, the problem still persists. A couple of the washers were a bit grungy with a black plasticy residue, but were still smooth to the touch and with a bit of lubrication showed no signs of being the culprit. If anyone had a link to buy replacement washers I'd be happy to replace them to see if it helps at all (or I could just buy any generic washer of the same dimensions I guess), but I just don't see it fixing this issue.