My wife's e36 tossed one of the quibo bolts and did the same thing. I put a new bolt in and torqued them all and after a few days of driving it smoothed out again. The quibo bolts are somewhat difficult to tighten. I think the torque spec is 95 ft-lbs (verify that). Inspect the quibo periodically to make sure it hasn't failed (cracks, frayed fabric reinforcement, loose sleeves).