Question Application stops rendering when other instance switches to VR

I have a Unity project with multiplayer and OpenXR. I want to demonstrate a VR avatar by starting the application twice, putting on a headset for application A and seeing it move in application B. However, when putting on the headset for A, B stops rendering.

In the Player settings, Run in Background is set to true.

When not putting on the VR headset, both A and B will render regardless of having focus. (I can see the non-VR avatar of A move in B's window.)

Any idea what could be causing this? If relevant, there are two different cameras in the scene, one for the XR Rig and one for the non-VR/keyboard+mouse control. Depending on whether a headset device is present and worn, either camera is activated and the other deactivated.

 

For some reason, setting the non-VR camera's Output->Target Eye to None fixed this issue. If someone understands why, please let me know.