As I stated, but more plainly;
The shadows you added to the top are now considered the edge of your image.So, you need that same exact shadow image on each frame of the side images, which will be very difficult to get even due to the transparency involved in shadows, which you may not see the defined edge, but wb does.
So, either use the frame settings as suggested first or place all four images, Top, SIDES, BOTTOM on one palette and add shadows all at once to one image, and recut it. This is why I suggested the first option.
