I don't know. Maybe it was not drilled and something accidentally caused it.
Sand and paint first to stop the rust from spreading, then plug.
I know some places that do rust proofing will drill holes in areas just like that so they can spray inside. That’s the only reasonable explanation. I’ve seen something similar on a car who’s window seals were leaking water and it was filling up inside the door and he elected to drill a hole instead of replacing the window seals. Now that was on a shitty car so I’ll stick with rust protection but are you sure there’s no other holes bc now I’m confused lol. Also they typically put a plastic cap to cover holes after drilling. Do the other doors have round plastic inserts where they may have drilled and you just didn’t notice? Hope this helps
This was the only hole I found in all doors. I think it was a paintless dent repair. You can see a small ding right above it on the door. Looks like someone opened the driver door and hit something. I was able to find a rubber cap and shove it up there so it’s all good now.
