@CSanderman
Usually you encounter this when you did not define a NavMeshBound Volume, since teleport project on it.
Simple solution: Put a NavMeshBoundVolume.
Complicated solution: modify the teleport function to teleport to something else (i.e. plane surfaces) without referencing a NavMesh volume.
Good news: Unstuck with Oculus compatibility. Seems that I had to modify PlayerController post-login settings to make it work.