To reproduce:

1. Download the attached project "Bartolo.zip" and open in Unity
2. Open "Loading" scene
3. Enter Play mode

Expected Result: Unity Editor successfully loads another scene during Play mode
Actual Result: Unity Editor crashes

Notes:
- This issue appears both on Windows and macOS
- Could not check on Standalone, iOS, Android because Build process fails
- Could not check on Unity 2017.4 because project becomes corrupted
- The stack traces and errors are shared in the Comments section

Reproduced on Unity 2018.2.0a1, 2018.2.15f1, 2018.3.0b9 and 2019.1.0a8
Not reproduced on Unity 2018.1.9f2
Regression on Unity 2018.2.0a1