DynamicMeshBuilder.cpp does not add a value to the InTangentY variable in the AddVertex function

int32 FDynamicMeshBuilder::AddVertex(
	const FVector& InPosition,
	const FVector2D& InTextureCoordinate,
	const FVector& InTangentX,
	const FVector& InTangentY,
	const FVector& InTangentZ,
	const FColor& InColor
	)
{
	int32 VertexIndex = VertexBuffer->Vertices.Num();
	FDynamicMeshVertex* Vertex = new(VertexBuffer->Vertices) FDynamicMeshVertex;
	Vertex->Position = InPosition;
	Vertex->TextureCoordinate[0] = InTextureCoordinate;
	Vertex->TangentX = InTangentX;
	Vertex->TangentZ = InTangentZ;
	Vertex->TangentZ.Vector.W = GetBasisDeterminantSignByte( InTangentX, InTangentY, InTangentZ );
	Vertex->Color = InColor;

	return VertexIndex;
}