Steps to repro:

1. Open attached project and 'test' scene;
2. Select 'Terrain' gameobject in the Hierarchy view;
3. Select any of the painting tabs in Terrain Component (e.g. Raise/Lower terrain);
4. Hover over terrain;

5. Notice that brush with blue highlight is rendered;
6. Input any number bigger than 49 to the Y-axis transform value (e.g. 50);
7. Hover over terrain.

Actual result:
Brush is not rendered. See attached gif video.

Expected result:
Brush should be rendered everytime, not regarding to terrain's gameobject transform value.

Notes:
- Reproducible in 5.6.0a3, 5.5.0f1, 5.4.3f1;
- Reproducible in both OSX 10.12.1 and Windows 10;
- Reproducible with any value more than 49.99;
- Reproducible only when increasing y-axis value in positive direction; not reproducible for increasing any other axes transform values.