Fit to Scene does not bake anything at all

To reproduce:
1. Open attached project
2. Open Untitled scene
3. Select NavMeshCube game object
4. Click Bake in NavMeshSurface component
Expected result: All the big cubes get walkable navmesh on top
Actual result: None of them do

Note: Fit To Scene must be checked
Note#2: If you uncheck FitToScene it will bake properly
Attached is a video with reproduction, under the name of "NavMeshFitTOSceneBrokenVIDEO.flv

Reproduced with:
Version 5.4.0a5 (806f333a7d81)
Mon, 30 Nov 2015 22:54:41 GMT
Branch: ai/navmesh/builder