URP Commandbuffer.Blit causes black screen in VR

[viliusnbg]

To reproduce:

1. Open the attached project. It is the basic URP sample scene with the SteamVR plugin
2. Open VRScene
3. Enter play mode. Notice that the screen is black and you can't see anything.
4. Disable the New Simple Blit renderer feature in the Settings/ForwardRenderer asset.
5. Notice that you can see the game view now.

This simple blit only does a blit from one temporary texture to another temporary texture and it causes the whole screen to become black as a result. This does not happen if VR is disabled (you can test it by unchecking the OpenVR loader in the project settings).

This is a very big issue, as it prevents us from creating any meaningful image effects in VR and Unity does not provide any alternative ways of authoring image effects.

I've reported the bug to unity and they were able to reproduce it, but they closed it as they don't maintain SteamVR:
https://fogbugz.unity3d.com/default.asp?1343852_4t9ppfktm0mbfvi2

I believe that this might still be a unity bug, but I don't have the knowledge of how VR rendering is handled and who is responsible for maintaining it. Hopefully someone from Valve could take a look at this and help me escalate/resolve this issue.

I've uploaded the project to my google drive since it's too big for github to handle:
https://drive.google.com/file/d/1_9mII56FwLrkW9_3rRJObxm6iu2f9Y1Z/view?usp=sharing

I suggest someone to reupload this into a more permanent storage.