Originally posted by grinsekeatzchen:

There are some times, when it gets REALLY dark. But you will ever see the glowing things. I had such a nightfall while a Serpent was with me and everything was pitch black but he was glowing. The same with the glowing eyes.

Yeah some how those glows aren't penetrating this fog.
I plan on getting a video of this when i jump on tomorrow and hopefully re-create it.
More and more seeming like a bug tbh.