Graphics.CopyTexture and Graphics.Blit problem

Sorry for my English.

Hi.
I have problems on my android device. (Galaxy A30). (I didn't check on the others).

Texture blurs when using Blit several times.

1. Copy a texture using CopyTexture.
2. I copy the resulting texture using the Blit method.

Each time I use the Blit method, the texture will blur.
More details can be found in the code.

Code (CSharp):

1.     public SpriteRenderer SpriteRenderer;
2.    
3.     // Sprite-Default material
4.     public Material BlitMaterial;
5.    
6.     // Two identical textures
7.     public Texture2D Texture1;
8.     public Texture2D Texture2;
9.  
10.     private Texture2D _tempTexture;
11.    
12.     public void Start()
13.     {
14.         // Create temp texture
15.         _tempTexture = new Texture2D(Texture1.width, Texture1.height, TextureFormat.RGBA32, false);
16.         Graphics.CopyTexture(Texture1, _tempTexture);
17.        
18.         // Copy Texture 2 to Temp texture
19.         Graphics.CopyTexture(Texture2, _tempTexture);
20.  
21.         // Create new sprite
22.         SpriteRenderer.sprite = _tempTexture.ToSprite();
23.     }
24.  
25.     private void Update()
26.     {
27.         // Get texture from SpriteRenderer
28.         var texture = SpriteRenderer.sprite.texture;
29.        
30.         var renderTexture = RenderTexture.GetTemporary(texture.width, texture.height, 0);
31.  
32.         renderTexture.filterMode = FilterMode.Point;
33.  
34.         Graphics.Blit(texture, renderTexture, BlitMaterial);
35.  
36.         Graphics.CopyTexture(renderTexture, texture);
37.  
38.         RenderTexture.ReleaseTemporary(renderTexture);
39.        
40.         // Each frame picture will deteriorate
41.         // If you remove "Graphics.CopyTexture(Texture2, _tempTexture);" everything will be fine.
42.     }