We found this crashing bug while giving an architecture visualization demo that involved multiple Quests. As you can imagine, for this use case, the crashing can occur fairly often.
It can be reproduced with Unreal Engine 4.27.2's default Virtual Reality project with Oculus OpenXR Plugin in use.
Repro steps:
Set guardian boundary on Oculus Quest to Stationary
Package or launch Quest build
While controllers are recognized by headset (not handtracking), get near the end of the stationary play area. move your head outside of the play area until the box appears that lets you choose between stationary and room-scale, then re-enter the play area. It may require a few tries. Sometimes it takes me up to 10, but in many cases it happens within the first 7 attempts. The screen will remain completely black, and you will have to exit the application.