Looks like you may have one or several problems. First you need to replace the moleskin on the rest. You can get some at the shop or just get good ole Dr. Scholls from the pharmacy. There may be several reasons it is only wearing on the one side. Upon release the rest doesn't drop right away if set up properly. At this point the arrow could be bending in toward the riser due to a stiff spined arrow or incorrect centershot placement. And/or the nocking point copuld be off drivng the arrow into the rest upon release. I suggest you replace the moleskin and try paper tuning if you haven't done so already.