I've had this issue at times as well. The tag end tends to get beat up a bit, at least in my old vest. I used to just snip off a couple of inches and then the problem went away. I now have my tippet in a nice little pouch of its own and problem solved. I also used to have my tippet on a spool on the outside of my vest and that was much worse as it got beat up pretty bad from the trees, weeds, and sun. Storage solved my issues.