Quote - I hadn't noticed that before, tekmonk, and I'm not clear why it should be. You can see that the seam is a light area on the bump map, so it should appear to be sticking out, as the side seam does.

Its because for the texture map, you have created one side of the texture then mirrored it for the other side, then copied one of the seams on the middle. This works fine for textures, cause textures don't affect lighting of a material. But bumps are different. When you flip/mirror a bump map, you are also mirroring the direction of light that created that bump. So when you render a bump map that has this sort of conflicting light in it, the odd parts will look reversed from the rest of the image.

Its easy enough to fix, but not if you only rely on the texture map.