where's your nock pt set, level, 1/8" high, 3/8" high? you may very well be bouncing off the shelf if you're not nock high with the dz or your rest may not be up long enough or too long, or your grip could be incorrect - have you changed your grip?. have you tried putting 1/4 turn in the top limb bolt? are you shooting level at paper? you got vapor trail right? i doubt that has anything to do with it. i took a couple of them apart when i was learning to pick up some tricks and they're nice. tried messing with the distance the rest is from the shelf?

but usually when you can't get rid of a nock high with a fall away the back of the arrow is bouncing off of something.