The gamma options resets every time I restart the game. Though the displayed value remains consistent (0.7) between sessions, the visual effect disappears and reverts to appearing as if gamma is set to 1.0. I have to readjust the gamma every time I restart the game.
Everything else is preserved. The actual number for the gamma setting is saved, but only the number. The effect isn't.
I can probably take some before-and-after pics if needed.
Quick update, this glitch doesn't seem to occur anymore. I think playing the game in the dark for so long might've caused me to hallucinate or something.