Can't remember if this has been discussed before or not. But neutral cities have a bug where they manage to produce a unit in 1 turn that normally takes 2+ turns to build.
For example in a game I am in, I attacked an active city that had 3 defenders (max it can have since it's had 3 defenders for many turns now). I lost the battle and only 1 unit remained. The next turn I arrived with another stack to find 2 defenders in the city. I was surprised since this city is making Sandworms which take 3 turns. So the city built a 3 turn unit in 1 turn instead of 3 turns.
It's an annoying bug that neutrals can have partial production in the queue so that they can produce a 2+ turn unit in 1 turn. It means the penalty for missing on a neutral is overly harsh.
KGB