Reproduction steps:

1. Open "GLClearIssue.zip" project
2. Open "GLClearIssue" scene
3. Enter Play mode
4. Notice that both planes are rendered grey/black
5. Go to the Scene view
6. Get closer to the planes
7. Notice that the appropriate color starts to render
8. Repeat with OpenGL

Expected Result: RenderTextures are the same as on OpenGL
Actual Result: On Metal, RenderTextures with MipMaps don't render properly

Reproduced with: 2019.3.0a4, 2019.2.0b4, 2019.1.4f1, 2019.1.0f2, 2019.1.0b1
Did not reproduce on: 2019.1.0a14, 2019.1.0a13, 2019.1.0a12, 2019.1.0a10, 2019.1.0a5, 2019.1.0a1, 2018.4.1f1