Hi. I just built one and have exactly the same problem with the Drive knob. It's totally usable as I guess I won't turn the knob while playing guitar, and even with synths I guess it's not the knob that I would necessarily turn when playing. But still, I was wondering : did anyone find out the reason why the Drive pot is acting that way? Just curious, as if that happens with another pedal, I'll know what problem I should target first (never happened before though).
I cleaned the PCB already, so I guess it's not the flux...
All parts are at the right values (voltage for caps)