For anyone still struggling with this (I’ve been for the past 2 years), the universal fix was to change “M_eye_occlusion_unified” like in the picture (I set it to 0.1, seems to look decent enough even very complex fog scenes).
This works in UE 5.7. Had this issues with all eye materials, including non-metahuman, have no idea what’s going on with that but this fix did it for me. (The default settings on the post from 2022 looks a bit different now, I didn’t touch that).
