This can be many things, all located within the BP_MotionController. I don’t recall having changed any teleportation function (everything under “Teleportation” in the functions list.
What I would recommend is to compare these functions to the ones found in the Epic VR template. Check if you missed something.
Look also on the components on the left, and check if everything is attached where it should be (arcspline, teleport cylinder, etc).
Finally check also if the SetupRoomScaleOutline function, I tweaked it a bit to accomodate Oculus Guardian.
Oh and one last thing I don’t think you work with the latest UE4-source version ("labelled as 4.16) but in future versions the function Project Point to Navigation will be updated and thou could cause a NavMesh projection problem if not changed.