Mine came off (not bumper since there is no bumper, but the cross rail the hitch adapter is mounted to) at 55mph.. I got some honking and pointing since the rear tire on the bicycle hit the ground and tossed up a large amount of smoke (no fire).. Got stopped. the only thing left conneted was teh brake control and battery re-charge lead.. Brakes worked as designed, No 2ndary damage.
Seperated car and hitch, stowed hitch, put wife in car and found parking (Very close) next AM found RV dealer, (Sorry can not help) next door was welding service Simpsons & Sons as I reall .... They re-built the broken brackets using steel that was half again as thick as the OEM, added some additional bracing to make it even stronger, and bolted it back on to the frame rails.
Still there.