I heard that same complaint years ago when they came out and everyone tried them,,,, it was either the string kept getting caught on bushes or they never heard the click... I figure its the excitement during the moment everything gets fuzzy.
If they work fine for people that's cool but try to concentrate on the anchor and pushing your bow hand right towards the spot on the deer like there's an invisible 20yd laser on the end of your arrow point then don't move anything (maybe to watch the arrow or deer) upon release.