Has this happened to anyone else?

Thanks for all of the input! The truck has lots of clearance, so I really doubt it was caused by hitting the truck rails. I did notice a small, what looks like a stress crack on the other side of the king pin and have heavily taped that with Gorilla Tape also. I looked inside the panel with a flashlight and don't see any stress cracks on the metal - everything looks good - no rust, etc. My thinking is that it is white plastic and is starting to give out. The dealer is getting a new panel and will let me know his estimate very soon. I will keep everyone informed when I take it to the dealer and see everything underneath.
Again, thanks for all the help!