Don't want audio to play on exit

The script is a super simple OnTriggerEnter2D but my set up is pretty messy. However, I've made a work around just using !isPlaying. Thanks for your responses and willingness to help but I think I'm sorted....still don't know why it was happening, but unimportant. Thanks again!

public AudioSource growlSound; AudioSource audioSource;

 private void Start()
 {
     audioSource = GetComponent<AudioSource>();
 }

 private void OnTriggerEnter2D(Collider2D collision)
 {
     if(collision.gameObject.tag == "Player")
     {
         if (!audioSource.isPlaying)
         {
             growlSound.Play();
         }            
     }        
 }