Paragon: Phase's skin turns white in a post-process

So in my scene I have a post process volume that adds Cel Shading and Outlines (AKA Toon Shading).

The problem I’m having is that Paragon: Phase’s skin turns white. Everything else shades properly. I’d like to understand the issue so that I can prevent/fix it in the future. I have dug around in the skin’s material and changed some parameters around but nothing I could think to try worked. If someone could tell me why this is happening, it would be very appreciated. If you need more info, please ask for it.

Here’re pics: Control and Toon Shading Post Process [Error] - Album on Imgur

I’m using this Cel Shading technique:
https://forums.unrealengine.com/development-discussion/rendering/114452-tutorial-simi-celshade-postprocess-material-work-with-light-color-point-lights-and-skybox