Mecanim calling StateMachineBehaviour script on empty state

I'm having a very strange issue with my statemachine.

I have a StateMachineBehaviour to play spine animations (3rd party animation software).
I noticed that empty states with no behaviours attached would reset the animation.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class PlaySpineAnimSB : StateMachineBehaviour {
5.  
6.     public string animation;
7.     private SkeletonAnimation skeletonAnim;
8.  
9.     // OnStateEnter is called when a transition starts and the state machine starts to evaluate this state
10.     override public void OnStateEnter(Animator animator, AnimatorStateInfo stateInfo, int layerIndex) {
11.  
12.         if( skeletonAnim == null ) skeletonAnim = animator.gameObject.GetComponent<SkeletonAnimation>();
13.         skeletonAnim.skeleton.SetBonesToSetupPose();
14.         skeletonAnim.AnimationName = animation;
15.  
16.         string currentState = "";
17.         if( stateInfo.IsName( "Idle" ) ) currentState = "Idle";
18.         else if( stateInfo.IsName( "Run" ) ) currentState = "Run";
19.         else if( stateInfo.IsName( "New State" ) ) currentState = "New State";
20.         else if( stateInfo.IsName( "Empty" ) ) currentState = "Empty";
21.  
22.         Debug.Log( "entered state: " + currentState + " and play animation : " + animation  );
23.     }
24. }

Now I have removed statemachinebehaviours everywhere, but somehow the code is still being called.
Here's a small part of my log.



I am absolutely clueless as to why this happening. Any help?