Door flexing

[44th Miss Inf]

Moved one of my crew cabs recently and noticed when I opened the driver's side door, the door skin flexed a good bit (probably close to an inch) in front of the door handle. I didn't have time to tear into it, but did check the passenger door and the doors of my other 3 square bodies and none of the others flex like that one does.

It's been a while since I have been in the doors of a square but I don't remember any brackets or braces to prevent this.

Will try to tear into it this weekend as I'm off. Is there a bracket in there I may be missing? I hate to take panels off a few doors to compare but will if I have to.

Thanks