OK so you noted that dropping displacement helps. That's interesting but probably not important. If the spurious blue dots line up with spurious displacement dots as well, they would become more obvious. Why would they do that, you might ask? Well a lot of vendors make mistakes on layers where they apply an effect to the wrong layer - a subtle one. They end up with an effect on multiple layers unintentionally - an effect that is synchronized by virtue of how the mistake happens. If the ambient map happens to have dots in it lined up with dots in the displacement, they would be emphasized.

Do this- set Diffuse_Value = 0, Specular_Value = 0, Displacement = 0, and Ambient_Value = 10. Render again and show. If you see blue or white dots, then for sure the ambient map has junk in it.

If you still don't see them, try Ambient_Value = 50.

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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)