To reproduce:

1. Create new project.
2. Copy in and Open attached scene.
3. Editor crashes.

Reproduced on Unity 2018.3.0a9

The scene is built out of many game objects with many random components (terrain included) And then all game objects are parented onto another random gameobject. This scene is saved. Opening this scene always results in a crash. Probably because objects with terrain component are parented onto some unexpected game object?

0x0000000141CBB46B (Unity) CreateGridLayout
0x0000000141CC521F (Unity) TerrainManager::RebuildConnectivity
0x0000000141CBE044 (Unity) TerrainManager::CullAllTerrains
0x00000001405CE9C6 (Unity) Camera::CustomCull
0x00000001405DD70A (Unity) Camera::StandaloneCustomRender
0x00000001405D798D (Unity) CameraScripting::Render
0x000000014177C48B (Unity) Camera_CUSTOM_Render