Moog Prodigy keyboard issue

When I go between the from any note higher than the middle F to the middle F itself the pitch does not changes, it glitches . When I play the middle F key on its own there is no problem with the sound . Its only when I transition, none of the other notes have this problem. Obviously you cannot from a low note to a high note due to the monophonic nature, but you can go from high to low. Would anyone know where this problem could arise from. I feel that its fixable and every other part of the synth works perfect with no problem.

I would start by carefully cleaning the keyboard contacts and buss bars.

Here’s a short video showing one method of doing it.

https://www.youtube.com/watch?v=Y7X6iMvhKEA

The video is not opening

Video plays fine here.