To reproduce:
1. Open project attached by the user
2. Select backyard grass desktop material (Assets->Desktop_Ground_Cover_Package -> Desktop_Ground_Cover_Package -> Backyard Grass ->Backyard Grass Desktop)
3. In inspector window notice that grass is partly black.

Another way to reproduce:
1. Import Speed Tree Desktop Ground Cover Package into a clean project.
2. Select "Backyard_Grass_Desktop" prefab.
3. Notice that grass is partly black

Expected behavior : Material should not have any black spaces when previewing it in inspector window.
Actual: Some parts of grass become black after regenerating them.

Reproduced with : 5.4.4p4, 5.5.0f3, 5.6.0f3, 5.6.1p1, 2017.1.0b1
Not reproducible 2017.1.0b2 till 2017.1.0b5

Note: After placing this material in the scene it looks as it should.