Runtime Vitual Height Fields and culling

Any Runtime Virtual Texture experts?
I have 2 questions
What determines shadow culling? ie as I move away from the Virtual Height Field mesh dynamic cast shadows disappear.
and
What determines visibility culling?
As I move closer to my Virtual Height Field mesh portions of it disappear.

Did you solve this?

Hi, you might need to build/rebuild the MinMax Texture (VHM details panel)