Ive noticed when using the mod matrix to lower the pitch an Octave, be it with Part A/B Semi, the OSC 1/2 Semi or the common Pitch Semi, i get inconsistent results. Often the results fluctuate by about 1 semitone. I noticed this when building patches today and trying to layer in a "sub" layer.
Im not very versed in old analogue synth emulations so I apologize if this is just an actual feature. Regardless though, i noticed my patches where sounding out of tune, and not in the good kinda drift way.
Video here showing what i mean, you can hear the obvious fluctuation when i go back to the Pitch Semi adjustment..
https://drive.google.com/file/d/1x7Fc5OaoOY9VfdaHL1-a_5wfKPO4YK4X/view?usp=share_link