Why does AudioSource.time return Infinity in Unity 5.3?

I have a MovieTexture file in my project, and I want to keep track with the time based on the audio time. It works fine in Unity 5.1, but when I switch to 5.3, the AudioSource.time just returns Infinity. Does anyone know what has been changed. Here is a snippet of my code. Thank you!

 public void processVideoFile(){
         GameObject.Find("Video Frame").GetComponent<RawImage> ().texture = movie as MovieTexture;
         audio =  gameObject.GetComponent<AudioSource> ();
         audio.clip = movie.audioClip;
         movie.loop = false;
         videoIsProcessed = true;
     }
 
 void LateUpdate () {
         if (videoIsProcessed) {
             if (!movie.isPlaying && !pausing) {
                 gameObject.GetComponent<LessonManagerScript>().loadVideo(gameObject.GetComponent<LessonManagerScript>().currentButton);
                 playButton.gameObject.GetComponent<Image> ().enabled = true;
             }
             if(!pausing){
             timeStamp = audio.time + timeOffSet;
             }
             Debug.Log("Audio time is: "+audio.time+" and timeStamp is: "+timeStamp);
         }
     }