I had this issue today. I recall after the WU3, I saw it twice and then disappeared. Today it came back again but it is really random, there is no a constant way to reproduce it. However, I have noticed it happening where I was flying over a photogrammetry city for the first time in a low altitude (it doesn’t exist in the rolling cache), could be that is the reason? Anyway, I restarted the sim, I have flown over the same region again, this time didn’t see it at all.