Ucupaint baking faces incorrectly

I’m using Ucupaint to texture a model for Unity. When I bake any of the texture channels on my model, it generates these strange white pixellated artifacts on the inside of the cut on the tail, as well as a few other places but it’s most noticeable on the tail.

I’ve tried messing with the bake settings and recalculating the normals/vectors, but nothing seems to work. I’ve had this problem before with this model and I got it to work eventually, although I have zero memory of how and I don’t want to stumble onto a solution without understanding how I got there and how to avoid repeating it.
The wounds do have a shape key that opens and closes them, the current pictures are from when I baked the colour channel with the wounds closed and it caused black tris to appear as well as the underlying white artifacts. I’d post more pictures of it but as a new user I can only have one image embed.

Is there a setting I need to change? Is it an issue with the normals? I’ve bashed my head against this issue so many times with this model and I really need help.

Welcome!

Are the cuts UV unwrapped? If they weren’t there on the model originally and you created additional faces when you made them, those new faces won’t be unwrapped at first.

It might also be a problem with the shape keys. Maybe you are getting the result of the bake with all the faces closed and collapsed on themselves? If that’s the case, maybe try baking on a copy of the mesh where all the shape keys are applied in the open position?