Wtf is going on here?

First of all, why does it trigger that weird high pitched sounding oscillator when I hit the STACK button?
And then, can anyone explain why each timbre sounds different not only when stacked but when not stacked, depending on which one is selected when I turn STACK on and off?
Here’s a video:
https://www.youtube.com/shorts/Kkj7POmqQeo

I also sometimes get this high pitched sound when switching between parts A and B, but I can’t reproduce it reliably.

Same here. Seems to happen most when I have a split patch with one timbre in unison mode. Assuming this is some kind of bus issue that can be tuned up in firmware. Let’s hope so.

Sometimes I have the feeling it happens (more often/more likely) when (nearly) all voices are used and/or when I switch parts.

But maybe I’m just reading tea leaves at this point. :sweat_smile: