Anyone fly above the fog/marine layer? I have the Mavic Air. I did, but had difficulty with bringing it home as the moisture layer was being detected by the down facing sensors.
As soon as you lose visual on your aircraft, you are in violation of the FAA rules. If you are coming up through the fog you risk a collision. You must retain visual line of sight.
See FAA rules - Option (recreational use) #1, paragraph D: "Fly the UAS within visual line-of-sight"
Link is here: FAA rules for non-commercial use
Yours is the third report of the problem of bringing a Mavic Air down in fog in the last 2 weeks. It does appear that the downward sensors are really upset by the fog layer and tho' it seems you can get the Mavic down - it takes a long time. I do agree with the comments above however, in that you do need to be aware that if you can't see your drone (or even the piece of air it's in!), then it's not safe to fly - and ... Wet + Mavic = heartbreak!