Two male NPCs sometimes switch gender to female after deleting the cache and starting up WoW. When in this switched gender state they retain the hair, face, skin, etc... of a male character, but on a female model. The two NPCs are Human Males.
One Forsaken Male NPC used the model of a Human Male and retained the skin, hair, etc... of the Forsaken Male. Issue hasn't been seen since deleting NPC and re-spawning it.
One Human Female NPC used the model of a Human Male and retained the skin, hair, etc... of the Human Female. Issue hasn't been seen since deleting NPC and re-spawning it.
NPCs are unable to use all of the skins available to them in WowModelViewer. I assume this is due to the way the models are created and applied to the NPCs. It's not a big issue, but I figured I'd let you know just in-case it is a bug or something. As a quick example, Blood Elves cannot use skins 10, 17, or 18 along with a few others.
when selecting NPCs, they often show the wrong portrait. As an example... I select a Forsaken Female with spky blue hair and a calm look, then I select another Forsaken Female with different hair and face and it'll still show the portrait from the first NPC. Then if I select a Forsaken Male then it either switches to the Man's correct portrait or it switches to the portrait of a different, previously selected, Forsaken Male. I don't recall a Female ever being shown on a Male portrait so it seems to be separated by gender, but it always happens.
-Valkryst
https://mega.co.nz/#!UBZlQKaL!8hZeWr-uSe9gcwI_tI2wzc8cehlTWE895Q8wkrcBvf0