SceneEnvironment.SkyBox does not work in XR

Using backgroundMode: SceneEnvironment.SkyBox in VR shows that the projection is not calculated correctly, so the background seems to move as the user looks around the scene. The workaround is to use a SceneEnvironment.SkyBoxCubeMap instead, but this is inconvenient when porting an application that already uses an equirectangular lightprobe as a skybox.