Steps to reproduce:

1. Open "test" scene in attached project
2. Press Play
3. Observe console, it only shows "Prepare started"
4. Open Test.cs
5. At the bottom of the Awake method, comment out the Prepare call and leave only the Play call
6. Prepare gets automatically processed before Play activates and console shows "Prepare finished"

Expected outcome: When calling Prepare() separately, videoPlayer preparation is initiated and finished.
Actual outcome: When calling Prepare() separately, videoPlayer does not initiate preparation, the call gets stuck in some sort of "Limbo" until something wakes it up.

Reproduced on 5.6.0f3, 5.6.0b8
Regression introduced in 5.6.0b5
Works fine on 5.6.0b3, 5.6.0b4

Note: Strangely, when in Play mode and the Prepare method has been called, but not resolved, it can be woken up by either selecting some window active other than the Unity editor or pressing the Frame skip button a couple of times (The one next to the pause on the editor :D )