City state missionaries?

Unless I have been hugely unobservant during all of my games I have never noticed a city state pump out missionaries. I have just started playing on Immortal so this could be a difficulty thing. Unfortunately the AI still can't seem to use them properly...

I've seen it from time to time, but I've never noticed the CS missionaries try to spread religion. They just seem to wander around.

Don't think CS's are pumping them out. Must be a captured Mongolian missionary or something.