Greetings! I've encountered a following bug (or at least I think it's a bug):

After performing a tribal ritual, an ancient complex appeared on my world map. I've cleared it, reformed a caravan and returned to my base. The ancient complex disappeared from the world map, yet the ritual screen says that it can't reward me with ancient complex, because there's already one in the game. The thing is, there isn't. I looted it and it disappeared. Is it a bug or am I doing something wrong?
Playing with no mods, only 3 official modules. Custom ideologion.

Regards,
Andrew