I for one still think there is something to the mist. On the David Braben youtube channel, he very clearly showed off a very misty crater making It seem like an important new feature and in the description mentioned "many things here are unfinished which I won't call out" in the horizons trailer the things we think are barnacles seem to be in a dark misty place. Then if we remember, the UA themselves seem to emit a kind of mist. Possibly the UA is creating a type of "atmosphere" in order to survive?
That's quite interesting.
I never found a planet with mist though, is it visible from orbit?