PolygonCollider2D doesn't cover the sprite in android

so it's my code

Code (CSharp):

1.  
2.  
3. using System.Collections;
4. using System.Collections.Generic;
5. using UnityEngine;
6. public class DROPITEM : MonoBehaviour {
7. public Sprite sp;
8. // Use this for initialization
9. void Start () {
10.    
11.      gameObject.AddComponent<SpriteRenderer> ();
12.      GetComponent<SpriteRenderer> ().sprite=sp;
13.      gameObject.AddComponent<Rigidbody2D> ();
14.      GetComponent<Rigidbody2D> ().velocity=new Vector2(5,3);
15.               gameObject.AddComponent<PolygonCollider2D> ();
16. }
17.  
18. }

so i have a sprite name sp,it's a gem,when I start the game,it should add some components to the object,(I made it to drop objects), in pc ,every thing works fine just like this video

https://streamable.com/h68zf

it adds sprite renderer,rigidbody2D and then PolygonCollider2D,but when I run my game in android,it seems that it adds PolygonCollider2D at first or for some reason the polygoncollider2D component won't cover the sprite !!!! like this video

https://streamable.com/bqtcx

how can I fix it???? it also tried to handle it inside a coroutine ,I added polygonCollider2D after 2 secs but the result was the same .

 

i think better to have prefabs and spawn prefabs with collider on board. I dont understand why u try to make it realtime. Coz all this operations very bad for mobile games.

 

there are lots of items,I don't want to create a prefab for all of them,i just add a spriteRenderer and choose it's sprite,then add Rigidbody2D and polygonCollider2D to drop the item. also i have tested this game on mobiles,there was no problem

 

it seems that when you add a polygonCollider2D to an object in run time,it doesn't cover it.(in android)