I think you missed my point the vector representation of the coordinate system and the representation on the matrix built by create world are not the same handedness.
I suppose i could be wrong if up right forward should be considered 1 1 1 at all i always thought that was the definition of a left handed coordinate system as the positive positive positive section of a cartesian graph with forward being positive.
What is in the the result of a Matrix.CreateWorld m.Forward and what is in a Vector3.Forward.
One only needs to print out to see they are not the same, (I didn’t make up those numbers)
If you negate only one dimension of a coordinate system it swaps the orientational handedness of the coordinate system which goes without saying left |/__ __|/ right