Enabling Tessellation on Materials in 4.11 causes geometry to Disappear

Any material that already exists in 4.11p1, with tessellation enabled, causes assigned geometry to disappear. Any material created within 4.11p1, with tessellation enabled and a base color, causes the material preview to be blank.

Checked in 4.10 4.11 and 4.12

Does not occur in 4.10 or 4.12

1 ) Launch 4.11p1

2 ) Create a blank BluePrint project with starter content

3 ) Edit the M_Chair starter content to enable tessellation and save -> no shader error message, but the chair doesn't render.

4) Create a new material, give it a visible base color and save, then enable tessellation and save -> no shader error messge, but the material preview is blank

Expected : Visible tessellation on chair. Result : Fully Transparent Geometry

Expected : Material Preview available. Result : Blank Material Preview