Generate Procedural Mesh

[=;203410]

The winding order it the same, but it’s calculating the normals backwards from each other.
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I think your normals are okay, otherwise you would not even be able to see one of the triangles (except if you had a two-sided material).
Looks more like the texture tangents are not calculated correctly. Look where the TangentBasisComponents is set in the VertexFactory of your generated mesh.

I had the same problem and correctly calculating the tangents fixed it for me.