Game Version number: EXP 1.2.1.86
Modded?: No

Currently the Navmesh does not work on open Doors!

If you enable the Navmesh Debug and checking a Door, there is a red NavmeshLink if the door is closed.
The AI can now open the door and walk through.

But:

If the door is already open, the NavmeshLink will removed and you can see a broken tile. The AI is not able to move through this open door.