That's because the information you were given before regarding the circus is incorrect. It's not about which city culturally claims the tile in question, but about which city 'claimed it first', regardless of whether it's currently within borders. You founded Ollan-whatever first, and the game detects that the two stone resources are near it. They are assigned to Ollan-whatever, and regardless of what cities you found next or what tiles you purchase etc etc they'll never belong to any other city. It's the exact same thing with the circuses so you need to extra careful where you settle cities close to these resources.