I think you have missed the point of the OP's (and my) problem. Clicking the left hand 'piano keys' in the PRV produces the incorrect note, and a different one to adding a note in the same horizontal pitch lane.
I also seem to recall when I had this playing a note on my MIDI keydoard - 'C' for instance would cause a different virtual note to be triggered on the PRV's lefthand side piano keys.
Its strange and very annoying when it happens