http://www.daz3d.com/forums/viewthread/11254/P30/

That has been an issue since C7. Carrara has issues with trasparencys/alphas close to the model when using GI. You have the same problem with eyebrowse on mill3 figures and hair on any figure. I've gripped about it repeatedly just to be blown off.

You can try turning off the item cast shaow, but this only works rarely.

Why do you think mil4 and genesis/G2 have no seperate eyebrow mesh now? Because they cast shadows; even in Studio.