Get unexpected surface normals result while using TextureBasedMorph

Meshes that animate via vertex deformations using worldposition offset display incorrect surface normals while animating. The reflections of the environment smear as the mesh moves making it look translucent or otherwise incorrect. The expected result gif was taken from 4.13 binary. The broken gif was taken in 4.19. 

Original Repro:
Follow this guild and finally I can't get correct surface Normals when the geometry vertexes are animating

https://docs.unrealengine.com/latest/INT/Engine/Animation/Tools/VertexAnimationTool/VAT_TL_Meshes/index.html

For simplified things, you can just go to StaticMesh'/Engine/Functions/Engine_MaterialFunctions02/ExampleContent/TextureBasedWPO/DemoBoxMesh.DemoBoxMesh'

This is a TexturebasedMorph demo we provided, it looks also has incorrect normals

1. Open any project in the editor
2. In the content browser, enable "Show Engine Content" in the view options
3. Find and open the "DemoBoxMesh" static mesh
   • Located in (Engine/Functions/Engine_MaterialsFunctions02/ExampleContent/TextureBasedWPO)

Result:
Observe that the surface of the mesh displays inaccurate, smearing reflections when animating with world position offset