[9.5.2 Bug] Production Zero

I just was playing a game and i captured a city and the city has zero production.  I checked to see what was the cause and the city has 0 materials in the Overview screen but below in the Resources portion of the screen it says Materials 3 (also Life Shard 2).  I am not sure if this is something that an enemy can do before they get conquered but I have no way of making this a useful city