I'm leaning towards this being a bug/oversight (extending the issue which was found for liberated civs triggering the ability again). Beside a potential unlimited source of easy eurekas/inspirations being too powerful for my taste, it clearly contradicts the way the ability is described in the Developer video: It is twice emphasized that it can only trigger once per civ in a game. I would recommend a bug report - or posting a save here ( [NFP] - [184.108.40.206] Kublai Khan Trait Exploit/Bug(?) For Liberated Civs | CivFanatics Forums ), where the forementioned sub case of liberated civs was reported. EDIT: Added link to related bug report.