2 of mine are a bit dodgy in fine mode & need replacing. Perhaps a bit different to you, mine just miss values so it takes a ton more turning. A is the worst & has no stiffness to it anymore, it works ok in course mode (pushing down). I’ve found that if I pull it up slightly it works OK. F is the other affected but it’s nowhere near as bad.

Mine is a mk1 and was one of the first batch bought at initial release.

It also has something wrong with track 2 which doesn’t make any sound unless filter 2 has some resonance applied.