By changing terrain heights in small area TerrainData.SetHeights doesn't update terrain collider.

1. Open project "SetHeightsBug" (attached by Lukas).
2. Play scene "Test".
3. Click mouse left button to spawn box, that going to fall on the terrain.
4. While the box is falling, click mouse right button to increase terrain height at the same point where you spawned the box (click it few times to make big hill).
5. You should notice that box goes threw hill and only stops at y = 10 (Because box size is 20), so it means that terrain collider was not update.

There is few things that I noticed, that by changing terrain in other place sometimes updates terrain collider and some points always updates. So I believe maybe there is small mistake in terrain code that caused incorrect terrain change detection, because when you change all terrains height terrain collider is updated properly.

Regression: 5.0.0f3
Reproduced: 5.0.0p2, 5.0.0b1, 5.0.0f4, 5.0.0f3