We had a member here (3/4flap) who had trouble with his G20 SF as well. He indicated in one of his posts that the rounds were feeding off to the left, much like yours seems to be. You might have a lemon. I would contact Glock as suggested. They probably won't give you a replacement gun right away but you could at least start the process if they can't get your issues ironed out.
"...the men under your command deserve your leadership."-OXCOPS