EPS in After Effects not transparent in 3D

I've brought an EPS card into AE with rounded edges on the rectangle shape and made it 3D. For some reason AE keeps filling in random corners white, despite its bring on a transparent background. Bizarely it appears bottom corners but not the top. And on a nother just one corner. I have tried comping the EPS, create shapes from vector version, redrawing the card from scrath in AE still get the same issue... what is going on?
Many thanks in adance
Joe
