Tessellation no longer working

Material Tessellation is no longer working in 4.11 Preview 2, 3, or 4. It is also no currently working in 4.12 Main.

Working: 4.10.2 - CL-2818068
Not Working: Tested in Dev-Release CL-2824708
Not Working: Releases-4.11 CL-2822657
Not Working: Dev-Main CL-2845412

1. Open UE4
2. Setup basic Tessellation Material
3. Apply to mesh in scene or use the material editor view
4. Change the View mode to be Wireframe

Regression: Yes

Results: Tessellation is not working.

Expected: Tessellation should work