Steps to reproduce:
1. Open the attached Project "OpenGL_SV_InsideTessFactor"
2. Open "Test" Scene
3. Enter the Play Mode to trigger Update
4. Move the View Camera around in the Scene Window

Expected result: Tessellation Triangles remain visible regardless of the view angle of position
Actual result: Tessellation Triangles are flickering when changing view angle or position or calling the Update

Reproducible with: 2017.4.18f1, 2018.3.2f1, 2019.1.0a14, 2019.2.0a1

Note:

Only reproducible on Win GLCore & Mac GLCore(Intel HD only)

Mac Radeon Metal - Shader not supported - correct as Metal doesn’t support geometry shader
Mac Radeon GLCore - works with NO glitching
Mac IntelHD Metal - Shader not supported - correct as Metal doesn’t support geometry shader
Mac IntelHD GLCore - works with glitching <———————
Win GTX980m DX11 - works with NO glitching
Win GTX980m GLCore - works with glitching <———————