Does your version work for you?
I'd go about it more like this
using UnityEngine;
namespace HutongGames.PlayMaker.Actions
{
    [ActionCategory(ActionCategory.GameObject)]
    [HutongGames.PlayMaker.Tooltip("Activates/deactivates a Game Object. Use this to hide/show areas, or enable/disable many Behaviours at once.")]
    public class ToggleGameObject : FsmStateAction
    {
        [RequiredField]
        [UnityEngine.Tooltip("The GameObject to toggle.")]
        public FsmOwnerDefault gameObject;
	public bool resetOnExit;
        public override void Reset()
        {
            gameObject = null;
	    resetOnExit = true;
        }
        public override void OnEnter()
        {
            DoActivateGameObject();
            Finish();
        }
		
	public override void OnExit()
        {
            if(resetOnExit==true){
		DoActivateGameObject();
		}
        }
        void DoActivateGameObject()
        {
            var go = Fsm.GetOwnerDefaultTarget(gameObject);
            
            if (go == null)
            {
                return;
            }
            if (go.activeSelf)
                go.SetActive(false);
            else
                go.SetActive(true);
        }
    }
}