How to reproduce:
1. Open the project "case_1235078-World_Space"
2. Open the scene "SampleScene"
3. Modify the viewing angle in the Scene View
4. Observe the results in the Scene View

Expected results: "Canvas" is not rendered on top of other GameObjects in every viewing angle in the Scene View
Actual results: "Canvas" is rendered on top of other GameObjects in every viewing angle in the Scene View

Reproducible with: 2017.4.37f1, 2017.4.39f1, 2018.4.16f1, 2018.4.21f1, 2019.3.0f4, 2019.3.8f1, 2020.1.0a17, 2020.1.0b5, 2020.2.0a7
Not reproducible with: 2017.4.36f1, 2018.4.15f1, 2019.3.0f3, 2020.1.0a16

Notes:
1. It is only reproducible when the Game View is not on focus
2. It is no longer reproducible after switching the Scene View to the Game View
3. It is only reproducible when Render Mode is set to World Space in the Canvas component