Kevin
It looks to me like the angle strip has pulled loose from the bed side. It would have been spot welded on from the factory.
Unfortunately, without repainting, the only solution I see is to drill holes and put some bolts in to secure it to the bedside. Is this an original bedside that you've restored and painted, or an aftermarket one that came with the angle strip attached? If the latter, I would contact the supplier about it.
