I've found that you can't just copy and paste voxels around in vxlse III. So I used to copy them to paint 3D (which displays them upside down for some reason) and copied them back after editing. It works with colors, but apparently not with normals.

In this picture you can see that copying them back and forth leads to a massive mismatch. Any ideas as to why this happening? Are normals too complex for paint?