Invoke acting strange

I am using an Invoke command to end my game after displaying an exit scene for a few seconds. When I open this scene I want it to display for a few seconds and then I want the game to stop. In the inspector I have "quitTime = 2" using UnityEngine; using System.Collections;

 public class QuitGameAfterTime : MonoBehaviour {
 
     public float quitTime;
 
     void Awake () 
     {
         print ("QuitGameAfterTime: Awake, quitTime=" + quitTime);
         Invoke("QuitGame", quitTime);        
     }
 
 
     void QuitGame()
     {
         print ("QuitGameAfterTime: QuitGame");
         #if UNITY_EDITOR
         UnityEditor.EditorApplication.isPlaying = false;
                 
         #elif (UNITY_IPHONE)
         Application.Quit();
 
         #elif (UNITY_ANDROID)
         Application.Quit();
                 
         #else
         Application.Quit();
         #endif
     }
 }
 

When I run my game and go directly to the exit scene everything works fine and the game ends after 2 seconds. Even if I go to a credits scene or goto a settings scene and then go to the exit scene everything works fine (game ends after 2 seconds). However if I play my game, leave the game scene and then go to the exit scene it does not work. The Awake function runs but the Invoke never does. This is a very consistent problem. I have no idea what could be part of my game to cause this?!?! Does anyone have any ideas?