How to reproduce:
1. Open attached project "WorldCanvasMultiMonitorBug.zip" and scene "SampleScene"
2. Open two Game windows. Set one to Display 1 and the other to Display 2.
3. Enter Play mode (both game views have the world space canvases in a background/behind white rectangle). This result is captured in "Two displays in editor.png"
4. Either Build&Run a standalone application or navigate to the Build directory of the supplied sample project's build(project -> build -> WorldCanvasMultiMonitorBug.exe, Windows only)
5. Observe both monitors

Expected result: both monitor screens look mostly the same, just like in step 3
Actual result: on display 1, the screen looks much like it did in the editor - the white block obscures most of the yellow circle and red text. On display 2, however, the yellow circle and red text incorrectly appear in front of the white block. This situation is demonstrated in the two attached screenshots named "Standalone Display One.png" and "Standalone Display Two.png".

Reproducible with: 2017.4.35f1, 2018.4.13f1, 2019.2.13f1, 2019.3.0b12, 2020.1.0a14