Cast Translucent as Masked in the Material Editor is no longer working

When enabling the option for Cast Shadow as Masked in the Material for a translucent object the shadow is no longer baked when building lighting. Using Stationary or Static Lighting will give the same result.

This is a regression of behavior in 4.10.4 where it was functional, and now no longer works in 4.11.0 and 4.12 Dev-Rendering.

Tested in:
4.10.4 - CL-2872498
4.11.0 - CL-2927265
4.12 Dev-Rendering - CL-2936247

ShadowAsMasked.png!

1. Open UE4
2. Setup basic material as Translucent with the Base Color and Opacity inputs used from the texture (AICON-Green from Engine Content Folder)
3. In the Material set the option for Cast Shadow as Masked
4. Appy Material to object in the scene with Stationary/static light
5. Build Lighting

Regression: Yes

Results: Shadow is not baked when using the flag in the material.

Expected: Masked shadow will be baked.