My 91 has done this. Only on high beam too. It did it when we were wheeling in this kind of, well "Deliverancey" sort of area. My wife freaked OUT. hahaha. I forgot about it til I seen this thread. Keep us posted...
91 Laredo, 4.0ho, TF999, Magnaflow exhaust, Yukon rear axles, Spartan Lockers, Posi locker, 3.5 inch springs, 1"MML, 1"BL, 1"shackles, trimmed fenders, raised flares, 35x13.50s.