Frankly, i'm no explore m12 engine nor manual very well yet, but there are some behavior on what would be want know answer.
Simple example.
Load new M12 instance, and
don't press any notes (from midi nor virtual GUI keyboard)
Load init Template Single preset (All Banks\Templates\>Template Single)
Now, in Filter section just up Freq knob to max and slightly up VCA2 filter knob level, to 8 for example.
Now we hear the sound of Saw's (from both oscillators).
Then just turn off both Saw (in VCO1 and VCO2 sections), and try enable Pulse or Noise waves - work (sounds) the same OK. But if enable
Triangle wave - nothing sounds (silence). Why ?