imagine that a first person game has a "get in a car and drive in 3rd person" mechanic

every time you do that, the camera has to shift around. but one time, some weird physics bug happens and the camera ends up pointing 90 degrees left when you get in a car

and then forevermore on that save, the camera points left when you get in a car. you can fix it by reloading a previous save before the bug happened and then avoiding the bug, but nothing else will fix it, and the bug doesn't exist in other save files, and won't exist in a new game if you start one

that's the sort of thing I'm talking about