Occlusion Seems very fuzzy

Hi I am actually testing the Area Targets with 

Add Occlusion Mesh and Add Mesh Collider,

I am using the most recent Vuforia engine and Unity 2020.2.2

but the occlussion seems very fuzzy.

(you can see it through image that I attached)

Is there any way I can solve this problem?

I made a map with Ipad Pro12.

Thanks!