Ok, through a bit of experimentation it seems that if a.) you click a city name to open the panel when b.) the icon in the lower right is NOT the "Next Turn" icon then the production menu messes up. If that happens the info panel (left panel) bugs out and doesn't go away when you exit the city. I also noticed the same issue as mnf above. However, if you access the menu by clicking the city name when the Next Turn icon is up, everything works fine.