Bug Annexing city's with Austria

[Nouco]

I was playing an emperor game with Austria.
I did diplo marriage twice.
And twice I got to chose if I wanted to puppet or to annex the city state.
After annexing the city I couldn't build a courthouse, even though I have mathematics.

 

[Juanholio]

I don't believe that's a bug. When you annex city states by diplomatic marriage they become your own as if you founded them. No courthouse needed.

 

[Nouco]

The bug is that the city's don't become my own, but get annexed...so it is a bug.