Every trailer I've ever towed with stiff springs and the proper tongue weigh bucks the tow vehicle. If you make the tongue weight light I find they buck much less but wander worse. If you have soft springs they can sway badly.
My 27 ft flatbed bumper pull always bucks, empty to 8 tons on it unless I'm driving really fast as the springs and tires are so stiff. Every bump they hit kicks the truck.