world displacement different than world position offset

When connecting a vector displacement map to the world position offset material input I get the proper displacement, albeit at a significantly lower than required resolution since it only affects the non tessellated vertices. However, when I connect a vector displacement map to the world displacement input on the material the vertices are displaced in incorrect directions. Further, the displacement direction changes when the mesh is rotated. Is this behavior a bug or am I misunderstanding something about the world displacement input?

This does not seem to affect vertices displaced along the vertex normal.

You should multiply your displacement map by a vertex normal for proper results.

That only works with heightmap based displacement. With vector displacement the results are different between the world displacement and world position offset inputs.

Had you ever found a solution to this? I put up thread here with the problem: World Displacement, Transform Bug or Limitation? - Rendering - Unreal Engine Forums