this is very bizarre sounding, this mult - CV thing. I was thinking
that possibly there is a short in one of the mult jacks so that a
siginal in there is making it to the faceplate of the doepfer and
interconnecting somehow that way to the VCO. But if this were
the case you'd see a billion other problems.

I split my mults from 1 x 8 to 2 x 4. I had to be careful when I did
this and I did get a short between signal and ground on one of
them because of the large blobs of solder used by Doepfer on
those jacks on the mult.

Pull the mult out and look closely. For giggles, with the mult
removed, get the same CV that was bleeding before and touch
the tip of the patchord to the faceplate of the VCO - do you get the
same thing happening If you do, there is a short in the mult
from one of the signals pins to ground making it to the circuit
through the metal can of the pots.

Turn the power off and read the resistance between the signal
tip and the ground ring of a patchchord that's plugged into the
mult. if it's anything less than infinite, this is probably your culprit.

Either that or the CV signal is of extremely high amplitude and
you're getting RF interference, but at this point I would look out
my windows for flying donkey's - it's highly unlikely.

If all else fails, send a letter off to Dieter.

hope this helps - let us know what fixes this bizarrity.

best,

Peter