Landscapes with Tessellation Material do not cast dynamic Shadows

Landscapes that have materials with tessellation applied to it will not cast shadows onto movable static meshes

Found in 4.19 CL# 4033788 and 4.20 CL# 4096272

Seems to be working as intended in 4.18 CL#3832480. This is a regression.

I have attached screenshots from 4.18, 4.19, and 4.20

1. Open the editor
2. Create a material that uses Flat Tessellation
3. Create a landscape and sculpt a hill
4. Apply the Tessellation material to the landscape
5. Place a directional light set to stationary in the level
6. Place a static mesh in the shadow of the hill
7. Build Lighting

Results:
The static mesh will not have the shadow applied to it and is fully illuminated by the direction light

Expected:
The static mesh will have a dynamic shadow cast from the landscape