Is this the 2015 Ford Flex?
There are 3/4 tons with 3000lbs of cargo capacity, and not the stripped down versions. The F-450 from 2011 would be as high as 4,200lbs of door sticker payload and a gas F-350 DRW could be as high as 5,000lbs.
Door sticker is NOT legal, but is manufacturer. RAWR + FAWR will far exceed GVWR. He is likely over GVWR, but under RAWR. Makes you wonder how they can rate the axles higher than the frame, what happens if you lower the front and max the rear? Can the frame handle the full RAWR???
It does look like the frame flexed just fwd of the camper mounts, so I would say that the camper had something to do with the location of the flex but I would have expected it to dip and not rise if the camper was the main cause. It looks like the frame jack-knifed it self.. just in the wrong plane. I wonder if they went thru a construction area that didn't have the bumps properly marked, I know I hit one 10 days ago that wasn't marked and in excess of 6", in a rain storm after dark, and the marked ones where about 2". Or maybe the truck rear-ended someone.
I think it would have bent more but the hitch/tie-downs appear to be on the road surface.