Error when using AudioSource with Google Play Games services

I am using the latest Unity 5.3.5f1. I have integrated my game with Google Play Games services and it is working fine already, I also have Unity ads and Google Admob as well. Right now I am trying to implement Audio into my game, I left this feature last as it is the easiest to implement but right now I have a problem.

I added a "AudioSource" component to the Main Camera. It is my only AudioSource component in the scene, heck even the entire game as I am only using 1 scene. I then dragged my BGM in .obb format into the AudioClip parameter and I turn on "Play On Awake" and "Loop", the rest are in their default settings.

Before exporting to Android, i tried playing the game in the editor and this error popped up but the game was running fine and the audio is playing so I guess its a runtime error. See image below.

I then tried exporting it to my Android Phone, Xperia Z5 on Marshmallow, it then crashed as I started it.

The error pointed to a specific line in "GPGSUpgrader.cs" where it says this. Line 107.

  AssetDatabase.Refresh();

Anybody had this problem before? Or would anybody care to give me a little help?

EDIT: In fact, this error pops up just by having a AudioSource component in the scene without the need to play any audio clip. So right now my game cannot have any Audio.