VR - floating HUD elements lose alignment when head-mounted display moved

[dewedin]

Brilliant work on the VR support, it is incredible to use, but unfortunately I am experiencing a disorienting bug with the floating hud elements when I turn my head as shown in the screenshot below (as you can see the target box has moved away from the targeted ship and the crosshair is not correctly positioned either). The example video in the VR feature release thread shows correct HUD behaviour.

Builds tried: 24.2, 24.0.2, Nightly
OS: Windows 11
GPU: Geforce RTX 2080Ti
VR HMD: Oculus Rift (CV1)
Issue occurs when using both Oculus and SteamVR runtimes for OpenXR. I also tried overriding Windows DPI scaling.
Command line: this is the same as default for the VR mod except amended resolution and addition of -no_ingame_options (reverting these changes has no impact)
-stretch_menu -soft_particles -dualscanlines -targetinfo -rearm_timer -3dwarp -warp_flash -aa -nolightshafts -window -no_vsync -capture_mouse -ship_choice_3d -weapon_choice_3d -ambient_factor 80 -spec_point 0.3 -spec_static 1.2 -spec_tube 0.3 -bloom_intensity 15 -parse_cmdline_only -res 1344x1600 -window_res 1344x1600 -vr -no_ingame_options

[BMagnu]

This is likely related to a similar report we've had recently on an index.
The fact that it now also appears on other headsets likely indicates a deeper problem and a regression that may have been added to the hud code more generally.
We ought to test whether this behaviour also appears in freelook (and/ or if some sort of lean is also applied).