Mystery Damage to my truck. From the camper??

I had one 10 mile section of porpoising road which sucked to drive on. This is the only thing that I think could have caused the paint to rub off. I just cannot imagine the legs getting so close to the truck. My brothers driveway was at a sucky angle but only traveled over it up and down one time. Not much cross wind and solid with the semi trucks passing.
The jack cannot rotate any closer in-word, even if it was lifted above the locking points.
I'll make some blocks to put in the front of the bed. I don't do bodywork so fixing the paint will be a pain for me.
Thank you every one for your help!