The bolts used to attach the strut to the body and the rear liftgate can accumulate fatigue damage if three factors combine. If the bolt is loose, the gas strut is over-pressurized, and the frequency of opening and closing cycles is higher than for the average customer, the bolt can fail.
Dealers will inspect for loose fasteners, if the fasteners are loose, the strut (and integral bolts) will be replaced. If the bolt shows evidence of torque, the bolt will be removed, larger washers will replace the existing washer and the bolt will be reinstalled and hand tightened to the target torqued.