A bug I've noticed for a while is - after I rebuild a razed city I can't buy production in that same city until after I refresh the browser. This happens consistently on all my games. I'm using Chrome on Win7. Its not interfering with game-play, just slightly annoying.
The city is sometimes labeled "Unknown City" and often can't even be selected. At other times it might display with an incorrect name and/or incorrect rebuild stats, even showing rebuild stats after it has been constructed.