Ok, I think I have found the possible solution.
Do me a favor and turn off your Material Overrides so I can be sure the suggested solution is the correct one.
After you have turned off your material overrides, go into your materials ‘Translucency’ section and change the ‘Translucency Lighting Mode’ to ‘TLM Surface.’
Translucency Settings
I cannot believe I overlooked this setting, but it is usually one of my first suggestions.
Let me know what happens.
Cheers,