I heard a sound from the right rear side of the car while driving on the highway and didn't make much of it. On parking, saw that the fuel flap door of my Alpine white X3 had fallen off. The fuel latch system and cap were all intact. Seems like a major design issue as there is no screw or physical latch tethering the fuel flap cover to the car, just pop-on clips. This better be covered under warranty!