Are you saying that this is not the case and that noise should not be triggering this way when notes are not pressed? If so: what settings would cause this to happen?
No. I'm saying that in Voice Input Mode the signal is'nt determined by triggering the notes manually. The Audio signal input in it self generate a Note On message, when the input signal exceed the Threshold.
That's why i suggested to adjust relevant settings, as they are the cause you search - so to speak. There must be something in your audio signal that exceed the Threshold.
Please consult the manual section "5.2.2. Gain and Threshold".
I assume you also can use a Gate plugin to control the signal going into Vocoder V.
BTW: I see i have made a spelling error in my first post. I assume you know i meant INPUT and not INOUT.