One possibility is the angle of the light sources relative to the surface. If the inside of the jacket isn't a distinct surface, what you're seeing is the light on the surfaces facing away from the camera, and there isn't any. But that will also show as a hole in the preview mode. There's also a render setting to not show "back facing polygons". Since it should be in shadow anyway, correcting this needs a little care. Apart from an extra light on the back of the figure, the obvious answer, you can try a low Ambient setting on the material. It often gets ignored, and yet it's one of the fundamentals of some shading models. Look up the Phong shader on Wikipedia. It isn't so important if you opt for ray-tracing and IBL, but you can limit that sort of material-based fix to just the one material, which can be useful.