Steps to repro:

1. Open attached project and 't1' scene;
2. In the Scene View scroll out to move it away from terrain.

Expected result:
Terrain is visible when scrolling out.

Actual result:
Terrain disappears from Scene view. See attached video.
Regression introduced in Unity 2017.2.0b4.

Notes:
- Reproducible in 2017.3a2, 2017.2.0b5, 2017.2.0b4;
- Not reproducible in 2017.2.0b3, 2017.1.0p2, 5.6.0p2;
- Reproducible only in Windows 10; not reproducible on OSX 10.12.5;
- Reproducible for any gameobject, though the bug is more visible for huge objects;
- The bug is only valid in Scene view; it doesn't affect actual gameobject rendering in Game view.