solved: too much disparity between near and far clip plane. far was 100,000 and near was 0.01. Changed near to 0.1 and solves issue. Must have something to do with limitation of camera viewport.
***original ***
In the video notice how in the upper left side there seems to be a sphere of influence driven by camera movement. It cuts off distant terrain with what seems like fog - however i have disabled fog for testing.
I’ve tested:
disabling enviro sky and weather, vegetation studio (plugins)
disabling occlusion culling
disabling fog
adjusting camera clip planes
camera clip plane far is set to 100,000. Entire terrain width is 60km.