Missing covert ops, bug or what is going on?

[ZHONN]

I fought an early war and got a city in a peace deal. It had the Spy Agency already built. The city was annexed. I hadn't built it myself earlier, so there it is and stays. I have researched computing. Still, I have no agents available.

Is there something blatantly obvious that I'm missing? Or is it a nasty, nasty bug?

 

[m15a]

Sounds like a bug. You shouldn't get national wonders from other civs.

 

[Halbbruder]

That occurs in civ 5 too, I think. It occurred because you hadn't built the spy agency yourself in your own cities.

 

[Pac-Dragon]

Can you sell the captured spy agency?