Reproduction steps:
1. Open the attached project "ReproProj"
2. Open the “/Assets/Scenes/SampleScene.unity” Scene
3. Make sure Oculus XR or OpenXR Plug-in is selected in the XR Plug-in Management window (Edit > Project Settings > XR Plug-in Management)
4. In Hierarchy, search for “Main Camera” GameObject and select it
5. In Inspector, make sure the Projection is set to “Orthographic”
6. Enter the Play Mode
7. Open the Stats tab (Game view > Stats)
8. Observe FPS
9. Observe the reflection of a Cube when the headset is moved

Expected result: Warning appears in the Console window and Projection is set to Perspective
Actual result: Cube reflection is changing shape and performance is worse by about 5 FPS

Reproducible with: 2021.3.35f1, 2022.3.19f1, 2023.2.9f1, 2023.3.0b5

Reproducible with devices:
VLNQA00379, Oculus (Quest 2), Android 10, CPU: Snapdragon XR2, GPU: Adreno (TM) 650

Testing environment: Windows 10 Enterprise 21H2
Not reproducible on: No other environment tested

Notes:
- Reproducible with OpenXR and Oculus XR
- Reproducible with Windows Standalone Player and Android Player
- Reproducible with OpenGLES3 and Vulkan
- The Projection is not automatically set to Perspective when Converting the Main Camera to XRRig