Post Process Indirect Lighting not working?

I have an interior environment for a game demo in which a room that has red lights with a post process effect would give off the room to be a red hue. Unfortunately, the post process effect for GI Indirect Lighting Color doesn’t seem to have any effect on the environment. Since I’ve switched the lights from static to stationary(the power will be out and the player will switch it back on with a flip of a switch on the fuse box) the effect doesn’t work anymore. Other effects such as bloom, auto exposure work just fine. I still have the Lightmass Importance Volume covering the demo environment. There are still some things I’m trying to figure out about UE4’s lighting and if this is an easy fix, I’m missing it.

I cranked up the settings really high and results were beginning to show. Thought it wasn’t working at all, that’s not the case. Phew.

I’m having the same problem after I’ve updated to 4.18.3 from 4.18.2. The only difference with mine is that when I kill all lights, my scenes is weirdly ambiently lit.