Fog of War problem on iphone6s

[deathguide]

     When I use Fog of War on my iphone6s,  the blur area appears to Mosaic, see the attachment.

Need help!

[ArenMook]

What happens when you move the camera around? Is it caused by a low resolution depth buffer, or is it related to texture filtering? What's your camera's near and far clip planes set to? I need a lot more information if I am to offer assistance.

[deathguide]

             When I move camera, the fog area is right, but the blend area appears to Mosaic. (the area called BlurVisibility)

It just like mTexture0 mTexture1 use FilterMode.Point, but I don't change anything.   I don't know it caused by  mTexture0 mTexture1 or depth buffer,

camera's near and far clip planes are 0.3 and 1000.   By the way, my device uses 64bit system.

[ArenMook]

Try playing with the far clipping plane and bringing it closer. I doubt you need the full 1000 judging by your screenshot. If that affects it, then the problem lies in the depth buffer resolution. If it doesn't, then the issue is with texture filtering. Perhaps iOS metal forces it to point filtering? What version of Unity is that with btw?