My post process volume misbehaves after restarting Unreal Engine

When starting an Unreal project for the first time, my post process works fine. Upon restarting, all Render Features break. I can change colour grading and related features, but everything under Render Features stops working. Furthermore, every object turns black upon rebuilding the lighting.

I’m at a loss as to why this is happening and would love some advice. Google has not helped at all.

My scalability is set to Epic.
The process is set to Unbound.
It does not work in brand new Levels.

This is 4.27.