I was applying my lidar to my kml terrain and my editor crashed. on reloading my kml terrain is missing and the lidar is missing that I applied to that area. I got a lot further than shown on the image before the editor crashed and saved frequently
I have found that after moving quickly around my route the editor doesn’t always keep up by loading the required tiles and it looks like some have disappeared. Sometimes I have to “save all” to force it to update the area where I am hovering. Try playing the game at a location near a missing tile and see if it then appears in game.