Gotta be a defect. The grip length (distance from bottom of bolt head to beginning of threads) should be 3 11/16" for AN6-42 if I am reading my chart right. I'll bet yours measures longer. I think you can even see where the grip stops and the threads should go to, but don't.
RV-9A - Done(ish) 4/5/16! Flying 4/7/16