I have a bushwhacker and have been using it for two seasons now. Late season is coming back in and I was practicing this weekend. I noticed on the bolt there was some wear on the nock. There is a line worn into the nock on the left side that goes down the entire nock and the line extends on the arrow shaft to the fetching. Seems there would be a burr or something on the rail. I had the front arms replaced before season under warranty but never noticed it until now. I shot a new bolt about 4 times before noticing it. Both bolts that were shot show the same wear. Has anyone experienced this and if so what is it from?