How to reproduce:
1. Create a new project
2. Create a new Scene 'test' in the Scenes folder and open it
3. Delete the newly created 'test' Scene
4. Select the 'SampleScene' and duplicate it (CTRL + D)
5. Open the 'SampleScene' without saving the 'test' Scene
6. Rename the 'SampleScene1' to 'test'
7. Open 'test' Scene

Expected result: 'test' Scene is identical to 'SampleScene'
Actual result: all of the 'test' Scene GameObjects disappear from the Hierarchy window and the Scene view

Reproducible with: 2019.3.0a8, 2019.4.4f1, 2020.1.0b16, 2020.2.0a18
Not reproducible: 2018.4.25f1, 2019.3.0a7

Notes:
Renaming the Scene to anything else after the issue occurs restores the GameObjects