Basically, whenever a female* NPC wears any kind of clothing that shows any part of the chest area, the body turns into some annoying yellow-intensive mismatched zombie-movie remnant. The face and neck look fine but the body underneath the clothing is totally the wrong color. Note that the basic undressed body seems fine. There's hardly any seam (well, relatively speaking) without clothing but it's like the body is getting "yellowized" by whatever clothes is added. This causes the seam between the neck and the upper body to be huge, which is quite an eyesore.

We're talking stuff like a nice pinkish face with a decidedly yellow body or a nice brown face with a yellow-brownish chest. In both cases, the body is the "right" race but the completely wrong tone.

Does anyone know what causes this? I've seen a vague reference somewhere to this being a shader issue with some Nvidia cards, but I've been unable to find more details about it, and searching this
board didn't provide anything either.

* I say female, but I'm fairly sure it applies to both genders. It's just that male outfits tend to have a higher cut and thus show less chest, which makes it quite a lot less noticeable.

So nobody has even heard about this graphical mismatch before?

The mismatch is noticeable and ugly even in the best of circumstances.
But, are you using any head/body replacement mods?

Edit: Just noticed: Note that the basic undressed body seems fine.
Are you using any user-made clothing/armor mods?

No to both. I've got a few gameplay tweaks running, but no texture replacements, no custom clothes / armor, and no mods that manipulate NPCs in general.