Buildings from Tradition Supposed to Be Like This?

[Peacemongerer]

So I have tradition filled-out completely. My empire is at 3 cities. Legalism gave me three Opera Houses, and in my experience, was supposed to give me one more free building when I got a fourth city.

Fast-forward. Darius DoWs me and I take two of his cities. I take Susa first and eventually annex it. I got a free aqueduct in the city from the start, but no monument, even after annexation. Is this intended or a bug?

 

[Monthar]

In this situation you won't get that 4th cultural building until you found a 4th city. IIRC, if you had annexed one of those captured cities before taking that policy, it would have received the free cultural building.