Addressables.UnloadScene returns IAsyncOperation object just like the LoadScene method, but for the UnloadScene method, IAsyncOperation never reaches state "Done"
Steps to reproduce:
1. Open attached project
2. Open 'TestScene'
3. Go into play mode
4. Press "Load Scene Bad" button
-Notice "THIS NEVER PRINTS" text is never printed in the console because the script never goes past yield statement

Expected result: Addressables.UnloadScene finishes the async operation with "Done" state and script can move past yield statement
Actual result: Addressables.UnloadScene returned IAsyncOperation object never enters "Done" state

Reproduced on: 2018.2.2f1, 2018.3.0a8