I noticed it too and on flat level ground,I usually don't do that.I am more like the pic posted.It was a matter of the positions I was putting myself in and what I had to do to get a good shot off.That is why we practice these shots,we can't get everything perfect so we must practice them.
The back muscles were taken out of the release as I said earlier and this must have been what I was doing subconciously to get a clean release.
I don't know if I agree with what you think is "correct",I personally feel there are things that are personal preference,this might be one of them.I have never put much thought into it,other than making sure I keep the release hand relaxed.
Check out Michael Braden with a wrist release,I have tried that and like it for competition but not sure I would like it with my hunting setup.
