VR + WebGL2 not working on Oculus Quest 1 and 2

[camelgod]

Description
Clicking the "Enter VR" green button on the bottom will result in a WebXR session with black screen, making the VR experience unavailable. It works when first entering the room (hubs wants to start xr session, click allow), but using the button will not work.

The Invite button inside the initial WebXR session is also completely broken and does nothing.
Clicking the Create button will show a prompt "Continue" but will break the website by going out and then back into WebXR session but this time with a black screen.

To Reproduce
Steps to reproduce the behavior:

1. Go to hubs.mozilla.com on Oculus Browser
2. Enter the room, exit webxr session, click "Enter VR" button
3. See black screen

Expected behavior
Clicking "Enter VR" should start a WebXR session without pitch black darkness.

Hardware

• Device: Oculus Quest 2
• Browser: Oculus Browser.

Additional context
Seems to have started after the UI update.
Avatar Head rotation and movement still works fine if you look at the avatar through another browser.

Here is the log from Chrome debugging / OQBrowser:

Here is another log from Chrome/OQBrowser on my hubscloud

[camelgod]

I was able to reproduce the same issue on hubs.mozilla.com using Firefox Reality. Seems like it is hitting the physics system?

Mozilla Nightly (81.0a1) Quest

After lots of workarounds and testing I got the VR loading but its all broken and I get:
WebGL warning: drawElementsInstanced: Multiview count mismatch: shader: 1, framebuffer: 2

[bekojang]

Running into the same issue.

[camelgod]

Update: I managed to get it working seting webgl2: false in hub.html on my own HC fork.

[camelgod]

So my hypothesis is that previously there was some kind of bug that made the client fall back to WebGL1. This is not the case anymore after the UI update, and it now loads WebGL2 successfully, but there is some kind of bug with Hubs + WebGL2 and Oculus Browser.

I still get the getPose error at random times:
Uncaught DOMException: Failed to execute 'getPose' on 'XRFrame': XRSpace and XRFrame sessions do not match.

[dvdsmthdvd]

I'm still having this issue. Has anyone found a solution? Seems like an error like this that makes Oculus Browser unusable is a big one and needs fixed!