Skylight reflections not rendering correctly on translucent materials

When attempting to create or use a translucent material the skylight reflection does not render.

Regression: Yes
Working:2946394 (binary)
Broken:2963582

1. Sync and compile UE4 editor in //UE4/Release-4.12
2. Launch Qagame
3. in the content browser click the green "add new" button and add starter content
4. from the modes panel drag a sphere into the level
5. apply M_Glass material to the sphere

Expected: the material will display correctly and the skylight will be reflected in the material.

Actual: The skylight is not reflected in the material.