The Raptor's bed-alignment problems have been noted on Web sites before, but a recent post on RaptorForumz has garnered some added attention. A group of 14 Raptor owners recently set out on an 200-mile high-speed off-road run, but only four of those trucks returned with their frames intact.
Update: An arguably important fact that was previously not mentioned by the damaged truck owners has since come to light - 10 of 10 of the trucks damaged on that particular run featured aftermarket springs in the rear suspension, a possible factor leading to changed suspension geometry. At least one other truck on the run who took the same course retained factory suspension bits throughout, and obtained no damage.
As illustrated in the pictures below, most of the trucks returned from the off-road trip with their beds at a rearward angle. Although Ford has yet to officially diagnose the problem, forum moderator BlueSVT (who also happens to own one of the damaged Raptors) blames the bed sagging issue on the Raptor's weak rear frame.
The Raptor's rear frame section isn't fully boxed, making it weaker than the rest of the truck. To make matters worse, the non-boxed section of frame thins above the rear axle to accommodate bump stops. Ford explains that this is intended as part of the rear crash structure in order to properly absorb energy in the event of a rear-end collision.
Under normal driving conditions, the rear axle has plenty of clearance under the bump stops. However, when the Raptor is taken off road at speeds upwards of 120 miles per hour, as documented to be the case with some of these bent frames, the rear axle can slam against the bump stops, bending the weaker part of the frame.
Ford has yet to comment on the phenomenon, but will likely have to answer to angry owners in the coming weeks.