I may investigate a different CV pitch:gate source (or calibration of A4 CV side)
I guess it’s theoretically possible the issue could be with the A4 and not the Monotribe
iirc The original Waldorf Pulse+ which I have does this too and it is a monstrous mono voice, more so than the later one … iirc, there was something about driving the synth voice by CV that was slightly erratic
anyway … more ideas here