Hi Holomind,
1. That solved it! I was sure I'd tried this but I might have hit the wrong checkbox on that line lol. Glad it works now, it'll help a lot.
2. I'm new to this render pipeline so I don't know how it operates fully. As far as I know I can't do it in overlay mode as unity will use the built-in legacy UI renderer in this mode. So I'm forced to pick between World or Screen Space - Camera if I want the UI to have the shader effect from a volume applied to it.
I tried your script but no dice! I created a new material with this shader, applied it to the UI mask but unfortunately it makes no difference. I checked out the Haunted PS1 discord and saw messages from 2023 saying that the haunted pipeline doesn't support UI Masking right now because it clears the stencil buffer. That would explain why the UI mask doesn't work by default even with your shader (I think)
Let me know what you think. It's no problem if it doesn't work, I can change my scroll lists to paged lists instead!
Also, I'm on Unity 6.2
Thanks!