What I observed in the use of Melodyne: When I first created a region, that is, select a track and then created a region, I was able, with ease, to move the notes with the stretch tool. However, I rendered that region, but then wanted to do some more editing and selected the track, again, and created a region of the whole track for a second time. In this second create region, scenario, the stretch did not work as it did with the first create region. Now, if I did something different, on long the way, I am not aware of it. Still, the second time through, instead of the notes moving independently, of one another and freely, they would move in snaps of a certain degrees and would stretch in a way that was unusable.
Well here I am, again, commenting on the stretching tool: I don't know what I did this night to make it work, and it worked just as you would hope it to work. Then, out of the blue, it started doing that thing -- where instead of moving the notes nicely and smoothly and be able to stretch them in a very usable, and very wonderful, way -- to moving in chunks or snap like half note movement, which are not usable.