The doors rust from the inside out. The factory did a crappy paint job inside the doors. Looks like they just swept the sprayer a couple of times pointing up, and not much paint got into the front crevices, where they commonly rust. In my 65 Dart, I removed everything inside the doors, wire-brushed, sand-blasted, sanded, even into the crevices. Then when clean, I sprayed and brushed Rust Destroyer everywhere, then yellow spray paint. Ditto for rear doors, trunk, every inner surface I could reach. On TV, they do a de-rust full dip of the body and sometimes a primer dip, like new car bodies today get.