Unity functions Awake() and Start() called multiple times

If you have accidentally dropped the same script on multiple game objects buried in the inspector hierarchy, there will be two instances of that script. Another occasion is that you have dropped accidentally the same script twice in one game object.

So the functions Awake() and Start() will be called multiple times.
Delete the excess scripts and leave only one and you will have the functions Awake() and Start() called once!