HoloLens 2 viewfinder appearance is unreliable only in OpenXR apps

[austinbhale]

Windows version: 22621.1376.arm64fre.ni_release_svc_sydney_rel_prod.240424-0600
OpenXR Runtime: 113.2405.31001.0 (preview enabled)

To reproduce:

1. Restart the HoloLens 2 (every time!)
2. Start an OpenXR application (e.g., BasicXrApp, OpenXR Tools Sample, etc)
3. Start MRC (e.g., via the "Start Recording" HL2 command or similar)

The missing viewfinder occurs after a fresh boot and the mixed reality camera has not been initiated outside of an OpenXR application. However, if you start the camera from outside the application and optionally stop it, the viewfinder will appear as normal in the OpenXR application, no matter how many times you start and stop MRC.

For more context. In the comments, @maluoi provides a possible cause:

I wonder if this is maybe a composition layer order issue? HL2's viewfinder composition layer sorts itself underneath [the OpenXR app's] projection layer in some cases. If that is what's happening, then this might be very tricky to solve on our end. We don't really have control over ordering of composition layers outside of our own.

[cwule]

Any updates on this, this bug seems to be quite consistent?