G8M renders with (terrifying) white eyes

See attached example.

What's bizarre is his eyes are the only problem in the entire scene. The female genesis 8 eyes render with no issues whatsoever, and neither does anything else.

Problem is always with the male genesis 8 model, attempting with the default of applying a custom eye material always results in the same white eyes.

Using the default Nvidia Iray engine for rendering. Is there some setting somewhere which might address this?