I think this is just more prominent now that the environmental fog has been adjusted. I play on a high render distance and very rarely see the sun/unloaded chunks from inside caves, but have noticed red fog a few times since the snapshot. I also notice that rain doesn’t increase the fog level underground, which aligns with intuitive expectations. I don’t think this is game breaking by any means, but it is a detail that might want to be addressed while fog is being tweaked.
Environment is Windows 11
Fair enough, happy that it’s been considered!