WebGL objects moves when screen resolutin changes

Hi, I have a game that include a game object fixed in the scene by this code.

 backgroundObject.transform.position = Camera.main.ScreenToWorldPoint(new Vector3(Screen.width / 2 + 150, (Screen.height / 2) + 35, 196));

I'm also using simmer.io webgl responsive template as well. Unfortunately, when my scene reloads, the gameobject slides to another position where it was. How to fix this issue?