Steps to reproduce:
1. Download and open the latest attached project(OC Link)
2. Uncomment line 76 in the UIDashBoardController.cs and comment line 74.
3. Uncomment lines 39 & 40 in the MenuSceneManager.cs
4. Build for standalone
5. Pick analyse and select option "bla" from the list
6. Wait for it to load
7. Press "Exit" in the top left corner
8. Press analyse and choose an option again

Expected result: old scene is unloaded and newly loaded scene is shown on the secondary monitor
Actual result: the last frame of the old loaded scene is overlayed on top

Reproduced on 5.5.5f1, 5.6.2p4, 2017.1.0f3, 2017.2.0b4, 2017.3.0a1

Notes:
-The old scene seems to unload properly after exiting a second time