Each voice has 2 OSCS and SUB OSC, and it’s own set of two filters.
If you hear a note playing, that’s one voice. It doesn’t matter if you’ve muted one OSC, or if you have pitched one OSC differently, or even if you mute both OSCs and just trigger the filter, it’s still a single voice.
If you play a triad chord and, as its fading out, you play another note then that is all four voices bring played.
If you are playing a triad chord and you play a duo chord then that will choke one of the voices in the triad chord, because that is five voices, and the A4 only has four. How it chokes, and which voice it chokes, is up to how you have set your polyphony.
If you have a note set to play longer than 16 steps and you play another note on the same machine then that will be two voices. A voice is the whole envelope of a single sound including its release envelope.
I hope that helps, it’s not the full answer.