Black faces when using depth of field

I’m using a cinematic camera and wanted to render a movie.

In the viewport, everything looks fine. When looking through the cine camera, some faces turn black when facing the camera.

I’m pretty new to UE. Can anyone point me in the right direction? Or tell me what the problem is here?

I’m working on an iMac running OS X 10.11.5 with an AMD Radeon HD 6970M.