Why is there color banding with "Bumped Specular" shader on iPad?

For some reason I am getting bad color banding artifacts when using the regular “Bumped Specular” shader. The “Mobile/Bumped Specular” shader seems to work fine, but it is much lower quality than the regular shader. On PC and Mac both shaders work fine.

Most references to banding like this on iPad is due to using anti-aliasing without a 32-bit buffer, but this is with a 32-bit buffer enabled and with AA disabled. It seems like Unity decides to switch to lower precision somewhere when using the regular shader on mobile, but I am relatively new to Unity and I am not sure where/how to tell it to not do that.

Any ideas how I can get this shader running correctly? Is there something easy I can try or do I need to just write my own shaders? I suppose there is no time like the present to learn Unity’s shader syntax.

Seems I missed a couple recent updates, and now that I upgraded Unity from 4.1.3 to 4.1.5 the problem has disappeared.