if you are veiwing someone on track, and you pit after viewing them(you are viewing them in spectate mode), the car will show what their mirrors last showed on the track. I know it happens with the FBM, but i don't know with other cars. Hard to see in the pic, but that's going up to the tyre bridge on BL1.

it happens with all cars in a way, when in a car, all cars have the same mirror as your car on track would, or the car you're riding with (if spectating).