This is all very interesting but I would like to return topic to the original stream.
Probably it would be better created separated thread for such discussion for avoiding mess.
My yesterday finds:
I used RG174 with shielding for ROT A and ROT B directly to pins as signal line. Menu clicks totally disappeared as in previous try. It looks like there is small interference by ROT A and ROT B tracks on the PCB due to long way.
But I still have VFO clicks with level more than noise floor on 40m. Also it level increases with increasing AF gain. I am going to check each OpAmp output for understanding where issue appears.
What do you think about this?