Is it possible the brakes on the camper are self-adjusting and were new? This is a common problem where they aren't fully adjusted so they take a higher brake controller setting but as they tighten with each application they eventually feel more and more touchy/powerful with every application so you end up needing to lower the brake controller output settings.
With the lower brake output settings do the brakes seem to react smoothly? Or do they lock up immediately? If they lock up immediately... view full answer...