I have bright white faces on the textures of my skeletal mesh.

I have a skeletal mesh from a custom rig I made in Blender, but it has illuminated white faces all over, meaning they even show in complete darkness, they don’t emit light on other objects tho.
It only happens on the skeletal mesh, I have combined meshes of the plane elsewhere and those don’t have any problems.
They remain even when I disconnect all the textures inside one of the materials.

When I look at the mesh itself, it also produces black squares.