As you can see in the attached photo, the Tourism calculation against Carthage says "0% bonus for Open Borders." However. . . I've had Open Borders with Carthage for at least 20 or 30 turns. Other civs I have Open Borders with do get the bonus -- why doesn't Carthage? This isn't a case of the bonus existing and then disappearing; I've never had the bonus (at least during the current Open Borders).