Question about transform tangent vectors of static mesh

Hello, I’m a newbie reading source code of StaticMeshOperations.cpp, and I notice that in function

FStaticMeshOperations::ApplyTransform

It applys same matrix on normal and tangent vectors, which is the inverse transpose of transfom matrix. But after searching online for a while, all people say that only normal should be transformed like this in case of non-uniform scale, tangent should use the original matrix,

link1 link2 link3

So which one is the correct way to transform tangents?