Texture filtering combines adjacent pixels to reduce the effective resolution. It is beyond the scope of your question as to why you want to do this, but there are some legit reasons.

Anyway, some texture authors do not understand this effect or are unaware of it. This includes Daz. As a consequence of their ignorance, they do not draw "outside the lines". In other words, if they fill the color map right up to but not past the seams, then the data on the other side of the seam is not consistent with the skin color. Usually it's white.

Texture filtering then combines adjacent pixels (white) with the skin pixels, resulting in a visible lighter colored line at the seams.

A texture that properly anticipates this effect includes a little bit of skin past the seam, so that texture filtering can do its job, which it has to do in 2D, not 3D.

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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)