Coal black skin during one render; fine the next.

lamoid_5f20d3e469

What could have happened (Daz Studio 4.22 Public Build)? I set up Render Queue to make 16 renders of a scene from different camers. In camera 15's render the model's skin was pitch black. In no other cameras did this happen. In particular 14 and 16 were fine. When I separately rerendered the camera 15 view, it turned out fine. What could possibly happen to cause a single render of the same scene to turn the figure's skin (picth or coal or deep space) black? Everything else in that view turned out fine -- even the clothes.

lamoid_5f20d3e469

Here is an example of the coal black skin erroneous render and the correct render. After getting the black result. I simply reran the render. Did nothing else. Then it worked. Note that only the skin was affected. Not any of the wearbles. What in the world?