Rigging and re-importing the eyeball mesh causes artifacts

I exported the eyeball mesh from the content examples to an fbx. Re-imported it without doing anything to it and that works fine.
I then rigged to an eye bone and now when I re-import I get black smudging on the iris you can see in the attached image.
I then tried using a permanent socket to attach the eyeball to my character mesh but for some reason it does not show up that way. A random primitive I attached like that did show up.
Something is going on with the eye I don’t understand. Anyone know?

Nevermind, I fixed it.
As per usual after an evening of fiddeling I decide to ask around, take a shower and get an idea to fix it. And it worked.

The normal import method needs to be to “import normals” and not “compute normals”.