I've been trying this, and sometimes it works, and sometimes it doesn't (Sonar Professional, x64, Manchester).
For example, I earlier I took an analog bass synth clip, dragged it to a new MIDI track, and it worked. It wasn't time-aligned, so I figured I forgot to shift-drag (as it wasn't a zero-aligned part), so I deleted the MIDI track and created a new one, did the same thing, and it came in as one long note.
It goes through mixing down audio, creating regions, analyzing audio, and the piano roll view shows one B3 note the length of the clip. Same result with a simple instrument track. I have a feeling it's Melodyne crashing or erroring, I haven't tried rebooting but that's next.
Edit: reboot did nothing, update to Newburyport did nothing. When I apply Melodyne alone to that track now, it just comes in as one long note, so I think it's maybe the Essential version that can't handle the tonality in the synth part, which is single-note, but lots of overtones and filters. And when I remove the RegionFX off of that clip, it's a flat clip now. I repeated this for a synth track that's not as rich, and it worked just fine.