The standard DAZ V4 shader includes an approximation for SSS that involves forcing some red in darker areas, as judged by the output of a Diffuse node. The mistake was that it forces red even when there is no light. Many 3rd party character sets copied this technique. It is has been promoted across the whole line now.

It is actually sort of my fault, since I posted the first example of this technique. I can't remember if putting color in where there is no light was in my original posting or not. When I first posted that shader (2006) I had not yet embraced mathematics in my shader work. I knew math, but I had not yet connected the dots that shaders are math, and if the math is f'ed up, so is the shader.

Now that I know that, these things are not a mystery at all.

So, always keep in mind:
1) A shader is math.
2) Most content creators don't know the math. They create shaders that behave right only in small regions of the solution space.

3. A shader can ignore lights - can create blackness inches from the sun and can create incredibly bright objects in complete absence of light sources.
   4) The number of possible wrong shaders or wrong behaviors VASTLY exceeds the number of right ones. There is only one physics in real life, but in the parallel universe of shaders, there are an inifnite number of absurd physics. Ask yourself what the odds are that the one you're dealing with matches the one and only true physics.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)