UserSceneTexture not working in Virtual Reality

User reports that UserSceneTextures used in Post Process Materials are only correctly rendered inside the left eye in VR.

Steps to Reproduce

1. Create a VR Template project.
2. Create a post process material that output a UserSceneTexture.
3. Create a post process material that use the created UserSceneTexture.
4. Set them inside the VR Template level.
5. Play in VR.

The UserSceneTexture is only render correctly in the left eye. Note that it should be possible to observe using the PIE VR debug mode, if you don't have a VR setup.