How to reproduce:
1. Open Unity
2. Load tester-submitted project(Link to OwnCloud archive in the edit section)
3. Open 'TessMaterialTest.unity'scene
4. In Scene view, fly around the sphere and observe tessellation artifacts
5. in Game view, notice tesselation artifacts to appear as black smears

Expected result: Unity renders the sphere without artifacts
Actual result: Unity renders the sphere with black smears

Notes:

• Could be related to depth buffer
• Changing 'Tessellation Edge Length' and 'Tessellation Phong Strength' properties, changes appearance of artifacts

Reproducible with - 5.6.5f1, 2017.1.3f1, 2017.2.1p2, 2017.3.0p2, 2018.1.0b3