How to reproduce:
1. Open tester-attached script (HiddenObject.cs)
2. Open any Unity project and import the script
3. Attach the script to any GameObject and enter Play Mode
4. Toggle Scene Visibility off by clicking the eye icon next to the scene in the Hierarchy window
5. Attempt to toggle visibility back on

Expected result: Scene Visibility gets toggled back on
Actual result: nothing happens

Reproducible with: 2019.1.0a13, 2019.1.4f1, 2019.2.0a1, 2019.2.0a4,
Not reproducible with: 2019.1.0a10, 2019.1.0a12, 2019.2.0a5, 2019.2.0b4, 2019.3.0a4
Could not test with: 2017.4.28f1, 2018.4.1f1, 2019.1.0a9(Scene Visibility toggle not yet implemented)

Notes:
Visibility can still be toggled back on by toggling it for each individual GameObject