Alright so, Morumo's answer is correct. You can reset the maintex for the face to just get rid of it, though you'll also have to replace the eyelines in that event...
It does actually look perfectly fine to me, though, but only when using the KKUTS shader.
The moment I turn KKUTS off, it breaks:
If your game automatically swaps to Xukmi's VanillaPlus shaders this may also be what's breaking it.
And my only guess is that it's because I have an updated KKUTS? You can grab the latest version of KKUTS from here:
https://www.pixiv.net/en/artworks/131615852