I had the same issue with the yaw on my Cyborg X at the weekend, I was in the middle of combat and it started to intermittently yaw to the right.
I took it apart and it looked ok, but then I found that one of the wires going to the yaw potentiomenter was loose, and only being held in contact most of the time by a nearby blob of glue.
These wires are probably the ones that get moved around the most, and are very fine, so I guess it might be a common type of failure and probably worth checking that everything is solid.