Working in 3D space - my image is split in two for some reason....

Please do not use the "Drag and Drop here..." field to add your screenshots. It is annoying to use and useless on some devices. Drag your screenshots directly to the reply form or use the toolbar to embed them. Cropped screenshots that don't show the modified properties of the problem layers are also not very helpful. 

When you stack up 3D layers is a really good idea to offset the layers by 1 pixel in Z before you move them. You can do this with the anchor point or the position property. You should also parent all stacked layers if you intend to move them together. Parenting also makes the Z offset easier to figure out.

This is called "Z-Fighting" and it's very easy to fix. The problem is occuring because both layers are occupying the exact same spot in 3D space and they're intersecting. Just push the zPosition of your whiteprint layer 1 pixel forward and you'll see it properly sit on top of the blueprint layer. If it disappears completely, then adjust the zPosition in the opposite direction (+1 instead of -1).