Bug with great people (I think)

[random11]

I had two cities in my empire that produced a GP on the same turn.
Since the GPP needed increaces each GP and there is no way one of the cities could make 100 GPP in one turn, I'm guessing that by pure chance both cities passed the points needed on the same turn, and saved me some GPP.

 

[Quantum7]

You didn't discover a technology that gives a free great person, right?

 

[MrCynical]

I'd say that getting a free great person from a tech is most likely, though even you were 100+ gpp in a city it could overcome the increase from the first great person that turn.

 

[random11]

You didn't discover a technology that gives a free great person, right?

I don't think so, but I can't be sure.
Pity I didn't save the game at this spot...