There are a couple of buildings that let you make more precise predictions of when the seasons will change. (-40% season uncertainty, or something like that).



You can only build one of each of these buildings in your empire. However, if you capture a city where another player has already built one, you can end up with more than one at a time.



In my current game, I've captured at least 2 such buildings (more, I suspect) in addition to the ones I built, and now my season prediction appears to be perfect. I get predictions like "34 - 34 turns until next winter".



Intuitively, it seem to me that the season uncertainty bonus from multiple copies of the same building shouldn't stack; the second building should just tell you the same information that you already gathered from the first one. Also, it preserves the incentive to get both buildings even if you happen to capture extra copies of the first one.

I would agree... and to be perfectly fair, if you can only build one in your empire, you should only ever have one in your empire. If you already have one, and you capture a city that has the same one, the latter city improvement should get demolished. Similarly, if you capture a city that has one, but you haven't built one yet, you shouldn't get to build a second one (and this is already the case).



I can't imagine that this fix could be too difficult to implement.