Hi,
I have been struggling with the encoders in my KPA for a long time. Rotation caused incorrect behavior (decreasing values instead of increasing, or strange jumps).
I thought it was the software's fault. Today I tried to use the Contact Cleaner Spray for electronics. I took off the knob and sprayed 2/3 times along the encoder shaft, then rotated it several dozen seconds both ways. Now they work like new 
In case someone needs it.
Cheers!