To reproduce:
1. Create a new project based on HDRP template
2. Create a new scene (do not use the default sample scene)
3. Import the terrain.unitypackage into Editor
4. Drag the prefab "Terrain_x10_y04" into the empty new scene
5. Adjust the main camera, let the camera see the whole terrain from topside down

Actual result: As soon as the camera sees the prefab, the editor crashes.
Expected result: Should not crash

Reproduced on: 2018.3.1f1; 2019.1.0a13
Not reproducible on: 2018.2.20f1; 2018.3.0b11
Note: happens only on Mac, can't reproduce on windows