Z2 crossfader glitching on the right hand side

Last week I set up a Z2 which has been boxed for over a year, and now the crossfader glitching. It's mostly working except, for when I slide it right over to the righthand side, at which point is cuts back to full left (see video).



Things I've tried:
- Recalibrating in Z2 settings on Traktor
- Recalibrating on the fader (with the little button on the bottom of the PCB)
- Opening it up and giving it a clean (as described here https://www.native-i...by-step.270961/)

Does anyone have any experience of this issue and have any idea on how I can fix it?

 

After a second session of opening up the fader and cleaning it, it seems to be working ok now. Hopefully it lasts.