Transform.translate stutter - Android game

Hello! I'm making a very simple 2D vertical scrolling game in which the player simply moves left and right to avoid obstacles. I managed to make the player movement, the background and other stuff but I'm struggling to make the obstacles move flawlessly down; this is the script that is attached to every obstacle, it simply moves it down:

 function Update () {
 
     //transform.Translate(0,speed*Time.deltaTime,0);
     transform.Translate(Vector2.up * speed * Time.deltaTime);
     
 }
 
 function OnTriggerEnter2D(coll: Collider2D) {
     
         if (coll.gameObject.tag == "Border"){
         coll.gameObject.GetComponent(UpdateScore).UpdateScore();
         //Destroy(this.gameObject);
         
         this.gameObject.SetActive(false);
         this.gameObject.transform.position.y=this.gameObject.transform.parent.gameObject.transform.position.y;
         
         }
     
 }

It resets the object position and updates the score when it hits the bottom border object. It should be easy but for some reasons when I play the preview the obstacles object seem to work fine but sometimes stutter while moving down; I'm sure it's not my pc because that also happens on my Nexus 7 and also the draw calls are around 7-10.

Does anybody know a way to make the stuttering disappear? I'm targeting android.

P.S Could it be something with collisions? my obstacles all have a 2d collider which I use to check if the player is hit or if the obstacle has reached the bottom.

Thanks in advance for any answer ;)