Not sure what happened from the description....

There is almost no force on the bumper itself when pulling from the recovery points...they bolt directly back to the frame through a piece of 3/8" plate on edge. No way it can bend in that orientation. If the side bolts aren't tightened fully, most of the load goes to the horn ends. If the frame horn end let go on one side only, that would put a torsional (twisting) load on the bumper though....

Unfortunately the frames on these trucks in this area are not very strong. Problems seem to be very rare, but there is something you can do to prevent it. There are two extra round holes per side in the bumper mounting brackets. Drilling these holes all the way through the frame with a 3/8" bit and using 3/8" bolts all the way through the frame will take most of the load off the horn ends and give two additional un-slotted attachment points. These holes are positioned toward the edge of the frame so that crushing the frame when tightening the bolts is not an issue.