my water shader looks weird

i’m going to make transperent water shader

i duplicaed and changed some parameters of M_Water_Lake of starter pack.

changed opaque to translucent

connected refraction and normal

it looks not bad.

but watch video please. that is so weird.

water disappear when i change camera angle.

there are no node about camera in my shader.

how can i fix this??

i’m newbie fo UE4 help please. thank you!