DTDT Thank you for sending your skeleton data file! The data does not seem to be particularly problematic, so perhaps there is an error in your code.
 
For your information, I wrote the following simple test code to check it:
public class CheckEventInt : MonoBehaviour
{
    void Start()
    {
        SkeletonAnimation skeletonAnimation = GetComponent<SkeletonAnimation>();
        skeletonAnimation.AnimationState.Event += CheckAnimationStateEvent;
    }
	private void CheckAnimationStateEvent (Spine.TrackEntry trackEntry, Spine.Event e) {
		Debug.Log("Event fired!: " + e.Data.Name + " / This event's Int value is " + e.Int);
	}
}
