Repro steps:
1. Open Scene1 from the attached project
2. Resize the game view
3. Observe the vertical box disappearing
4. Change in the Main Camera the rendering path to Forward, or set HDR to use the Graphics Settings
5. Observe the game view renders normally

Expected outcome:
The Game view to render 100% of what should be visible

Note:
- Regression in 2019.2, does not repro in 2019.1.0b5