Scene Capture view not matching player view

Hey there, trying to get a portal system working but running into some issues with the screen captures.

If I select “SceneColor (HDR) in RGB, 0 in A” as the scene capture source, the portal looks correct, though there is no post processing, including anti-aliasing, making the result look sharp and jagged on edges.

To fix this, I need to change to “Final Color (HDR) in Linear sRGB garmut”, which has post process and anti-aliasing enabled. The issue is, this mode seems to mess with the colours of the scene, making the seam on the portal, and the “pop” when going through, much more noticeable. Ive disabled vignette, bloom, auto exposure on the scene capture which helped with other discrepancies, but not the colour.

On first glance, it looks like its just raising the temperature, so I attempted to lower it on the scene capture, which worked for the specific area I fixed it for, but then makes other areas look even more off if I use portals in them, especially in low light/dark areas. I’ve tried messing with/disabling all other post processing effects to no avail. If I make all materials greyscale, the colours match properly. I’ve also noticed that the difference is more noticeable with warmer colours/lighting.

Heres the initialisation/settings used for the scene capture and render target:

No idea whats going on or whats causing the change in colour, any suggestions would be appreciated!