I just wanted to add a comment that have been experiencing some voicing issues that are similar to what you've described. Whether I've cold-started the PB or let it warm up for sometime, I've experienced some voices buzzing or sounding like the filter is completely open, or glitching from open to closed repeatedly. It only happens for a 2 or three of the voices, whereas the others in the patch act as they are programmed. I've done a full recalibration and it fixes the problem temporarily. But it comes back. I've read other posts about similar issues but I haven't seen a permanent solution yet (just a recalibration, which is not something that I want to have to do several times per day...)
Cheers,
John