In towing, I have had problems when either...
1. The towing rig (bar, would include base plate) was loose
2. Front suspension of the towed vehicle was worn or damaged
... towed vehicle would jerk back and forth. So hard it'd sway.
There's also an oscillation that can happen. Apparently there are certain pickups that Ford doesn't have an answer to. The way to stop it is to stop the vehicle then it's OK till it happens again.
But I read your opening to say that you find the Jeep's wheels cut hard over to one side. Is that correct? If so I'd venture the first rough patch knocked the Jeep's wheels off center and they went into hard-over lock. Then under the momentum of your heavy coach, something got bent. What does the Bus weigh? 30,000 Pounds? That's irresistible force against a tow bar or unibody vehicle.