The problem of NavMesh and NavMeshObstacle in Unity 4.6

Hi, everyone.
I got a problem of NavMesh and NavMeshObstacle in Unity 4.6

I made NavMesh likes below.


And I put a GameObject attached BoxCollider and NavMeshObstacle.
The property 'Carve' in NavMeshObstacle is checked.
So the part of NavMesh is removed. It is not a problem.


But in Unity 4.6, when I disabled or moved top the GameObject, the part isn't repaired.
So a character attached a component 'NavMeshAgent' can't go left to right.
On the other hand, in Unity 4.5, the GameObject is repaired.


This is the problem in Unity 4.6. It doesn't occurred under Unity 4.6. (I use Unity 4.6.3 f1 and 4.6.4 p3)
When I tested it in Unity 4.5.5, it doesn't occurred.
But I don't know this is a bug in Unity 4.6. If this is a bug, I'll send a bug report.

Thanks!