fog bug,some object not work

i want to use fog , but the model which is loaded by AssetBundle is not effected ,i can not resolve it

then i try to use GlobalFog.cs in Standard Assets, but the cloud in Quantum Theory isnot effected…i am very confused…

Who knows the answer to this question?
I tried using fog in Lighting Settings, but id didn’t work for AssetBundle in Unity 2019.4.20f1.