This may be odd but a couple of bows that have done that at the shop I've taken and put a couple of twists in the cable. I'm thinking that it moves the nock travel more to the center of the bow. The other thing is to start over on the set up of the bow, tiller, poundage and such. Having the rest pick up the arrow at the last possible second on the shaft may help. Think about what the arrows doing when coming off the sting. drop aways tend to need a more perfect spine some times due to fact that the laucher is not there to correct the arrow during the shot cycle. try moving the rest back to weaken the arrow and forward to stiffen the arrow. some times it does'nt take much.