I think that's normal behavior. You can set the time after which the background should get updated when scrolling through your movies. If this timeout is set to one second the background changes after exatly this time - to the default in your case.2. All backdrops work fine, but if you scroll past one that do not have backdrop, the next one will be displayed for one second, then it will switch to default backdrop.
sooo,,,,,the wrong backdrop is right one?? you must wait 1sec+ until you go to next, will take an hour to go trough my movies in that way!!!
Should I i set the timeout to 0??? No, this must be a bug!! It should reset the timeout counter if I go on to the next one.