This bug has been reported before but here is a turn one save that you can use to perhaps figure out what went wrong. Hopefully the fact that its reproducible on turn 1 will help you out.
You can see that oracle ceresa in the top left corner of the map will not settle a city, and the rest of the sovereigns do. I am using custom sovereigns, I hope that doesn't prevent you from loading the save. I can upload them too if you want.