I have a hard time believeing that PSE would design a bow that has issues of this sort from normal wear. I've never shot the stingray so I can't say for certain. I'd suggest posting on the PSE message board.
http://forums.pse-archery.com/
Diane Watson and the gang there are very helpful and won't stear you wrong. If this is normal they will know and tell you so. If not the will direct you to the appropiate channels to correct the issues(This will start with your local dealer). PSE will take care of you if there is a problem.