Understanding Poly count in statistics

Trying to optimize a cad model for mobile
I notice that in Game view when the object is out of the Camera frustrum the poly count is
Tris 135k Verts 119k

But the moment it is in the frustrum it drops to
Tris 1.7k Verts 5.0k

S0 confused!
Does this mean that their is automatic culling when an object is seen by the camera?
And NO culling otherwise?

Shouldn’t there be ZERO Tris and Verts if the mesh is not visible to the camera?

Upload some screenshots from statistics and game view in different states