Audio Snapshots TransitionTo FadeOut

I am having a problem where I have 2 snap shots, one the default snap shot while the game is running, and another snap shot with all the audio groups attenuation set to 0 for fading out between scenes.

When calling myFadeSnapshot.TransitionTo(some seconds) only 1 of the 5 audio groups actually does the transition. Most important would be having the Master group fade out but the transition never takes place.

Why would some audio groups make the transition but not the rest?

 

A little follow up here,

I have a settings page where the user can set the audio levels for the music, game, and voice effects in those groups. I use

    public void SetMasterVolume(float value)

    {

        mixer.SetFloat("MasterVolume", ConvertToDecibel(value));

    }

to set the different groups at Start. If I don't set the groups before hand, i.e. don't use SetFloat at Start then the snapshots work as expected.