if you tuned your VCOs it might be that if there is an error in the MIDI to CV conversion on the shuttle, it’s hidden because of the tuning you did. So that would explain the situation. But i’m not saying there is a problem with the shuttle, it’s just a thought.
you should look at the polyphonic wavetable preset, it uses multiple voices, 8 of them in total.
the MIDI module only supports omni at the moment (basically it ignores the MIDI channel). But you can put each MIDI module into a seperate voice, use the V1-V8 toggles on the P-page of the MIDI module. You can see an example of this in the polyphonic wavetable preset.
The incoming MIDI notes will be assigned round-robin style to the MIDI modules according to their voices. So the first note will go to the MIDI module set to V1, the second note to the MIDI module set to V2, and so on.
In the upcoming update there will be about 60 presets included with multiple example polyphonic patches.