There is a bug when using the Highlight layer together with the xrHelper.
The following playground can be seen as an example:
https://playground.babylonjs.com/pg/9K3MRA/revision/133
I’ve testet this on the Oculus Quest using the oculus browser. When I set the highlight layer the background turns black and only the highlight layer is visible.
https://playground.babylonjs.com/pg/9K3MRA/revision/161
EDIT: Apperently a similar thing can be achhieved by using the Glowlayer. Here the problem doesn’t occoure. That doesn’t change the fact that the other bug still exists and this sollution is not optimal.