I made a clean patch and project, to make sure there is not some weird modulation going on.
I start the playback and everything is fine, but if I stop the playback, the release of the note is going to C3. It sounds like a pitch envelope with the “wrong” settings. The Midi-CV module is set to monophonic.
it appears that when you stop the daw, no more voct signals are sent via the midi CV inside rack. but since the release is still active on the envelope your patch continues to drone but with the values set on the frequency knob on the VCO.I would add a stop trigger to mute all output of the patch when you stop daw. or maybe sample and hold the last voct value sent