VR Motioncontroller Template Problem with Navmesh

Hello, I am trying to make a Level starting with the VR Template and the Motioncontroller Map. But sometimes I get problems and the Teleporting is not working anymore. It looks like this on the Oculus (see image). It seems to have something to do with the Navigation mesh I guess. But I have a good NavMesh. I really cant make the level work anymore when this happens and I need to start from scretch with the template.

The Navmesh looks fine.