Excessive wear on one side of your prong rest may indicate an improperly positioned centershot. You may need to adjust your rest to the right. Or it could be arrow flex like JDoyle said. Or it could be that you are torqueing the bow when you shoot.

Are you getting good groups with broadheads or with field points? Fixed blade broadheads aren't very forgiving when it comes to centershot: they need to be launched as straight as possible from the bow. Try shooting some practice broadheads and see what happens.

If you are still getting good groups then I wouldn't fuss with anything. Good hunting.