Tri-fold Tonneau question

Ok, has anybody had trouble with the front corners of their tri-fold tonneau cover not closing tight on the bed rails? If so how did ya fix it? Mine stay about 1/4" off the rails on both sides. The bolts are as tight as they will go and the corners are still off the rails. Wouldn't bother me a whole lot but the wind goes up under the corners and it acts like a parachute.