When rendering a camera to a render texture (for a portal effect), it seems to under certain circumstances skip rendering the
red channel entirely.
I cannot put my finger on why this might be happening at all. It seems to depend on the angle of the camera, as it stays color-shifted (or not) if I keep the camera in the same position/rotation.
As can be seen in the below pictures, the camera preview does in fact pick up on the full color.
If it is perhaps relevant, I am working in the URP with HDR enabled.
EDIT: Upon further investigation, it seems it can actually skip any channel, it just does red far more often. I just ran into a case where only the green channel was rendered…
It appears to be linked to being forced to render HDR color, for whatever reason?