>>717433936
It was just the glowing weather fading to the normal world weather. I realized it because I once played around with the Weatherman settings to get that mixture.

Oh neat, final cutscene spoilers
Living Memory is restored to it's golden form for the plot reason mentioned before, activating the method to restore locked memories from the regulators. It's like it was from before, but with normal weather instead of the dark default glow..