Started a new play Easy, soon got again this bug and first time that it wasn’t Scavenging site, but a Haven. I failed find a cause, or how dodge it, so I’ll stop play, this is a game breaking bug when a bug generates time lost in a game based on a time rush.
EDIT: I removed the trading comment in OP, no trading yet in this last case. And I removed the comment that it was only for Scavenging sites, just not always, with no clear logic.
Haven offered locations for an exchange of materials and tech. They returned 5 sites. One was an “Exploration Site” with a magnifying glass icon. Going there there is no option to Explore, only scan.