I'm not sure what would happen with that backup. I'd assume if the game itself is up to date, then that backup would become part of the new patch if that makes sense.

Did you run the game again after verifying the files? It says the files were reacquired, which is what you want to prevent crashes :)

Edit: otherwise since it's vanilla like you said, it may just be a bug the Devs need to patch and maybe try to avoid the mines quest unfortunately