Yes, any fly with Bulk will spin on the back cast and/or retrieve if not symetrical and or if the face is not perpendicular to the hook line. It takes trial and error. In the interim, I'd suggest you try the Lefties bug design I've posted a few threads down. I tie them all the time in 10# and never have this issue. They are VERy effectivve on our panfish and bass. I'd love to hear how they work for you. P.s. using a loop knot wil also help.