We had a guy pull in next to us last Summer in Canada with the bottom of his ladder ripped right out of the rear cap of the fiver. Two bikes on the ladder rack were nice and tight. The bottom mounts however were jusr screwed to the fiberglass skin with sheet metal screws.
I don't remember the brand of trailer, but I guess the manufacturer thought that the upper ladder mounts would carry the weight and the bottom was just for stability. The bouncing of well secured bikes (It is rough back there at highway speeds.) seemed to put enough upward force on the screws to rip them (and chunks of FG) out.
He was looking at makor repairs.