[Solved] Some NPCs are blue, purple, and red?

I don't know how to describe the colors precisely, so I insert the screenshot. It's so wired that some of the NPCs are "rainbow" colors. I know that some CC objects may be like that when they miss a texture they need, but I'd never seen an NPC like this. Please help me out o(╥﹏╥)o

Now I find the reason: a default skin replacement cc.