UMCP-2 Headphone Mix Unresponsive

Hey everyone.
For a while I've noticed that the 'Mix' dial on the headphone section of my Control Pro 2 is unreliable. I can turn it and the corresponding dial on the screen starts to turn. If I start to turn the dial too quick however the onscreen dial will stay put, as if it's been dropped (if that makes any sense). I then have to dial back over where the marker is and 'pick it up again.
Does this happen to anyone else or is it just me?
For a while I've noticed that the 'Mix' dial on the headphone section of my Control Pro 2 is unreliable. I can turn it and the corresponding dial on the screen starts to turn. If I start to turn the dial too quick however the onscreen dial will stay put, as if it's been dropped (if that makes any sense). I then have to dial back over where the marker is and 'pick it up again.
Does this happen to anyone else or is it just me?