Ehy guys! I can't believe I notice this only now, after so many years of playing this game, but you have to play scenarios or messing with the rules to notice it. The thing is that every terrain in the 3rd position in the rules.txt file get their base shield production totally voided, it doesn't matter which value you put there in the rules.txt. It correctly show the rules value in the Civilopedia, but if you check it inside a city you see that you get no shields from there. Now, if you play the Original game you'll never notice it, because that spot is taken by Grassland which already gives 0 production. Even in other scenarios, like Extended or Fantasy, that spot is given to terrain with 0 basic production, so everything works as intended. It seems that spot is hardcoded to work this way. But on most maps in the Scifi scenario (all but Funestis) that spot is taken by terrains that should give shields: so it says in the Rules files (and confirmed by Civilopedia descriptions which talk about "getting material out of it"). This is why I think is a bug (at least for the scifi game): without those shields those terrains get very underpowered in comparison to the rest of the map and it's clearly a problem since they're intended to be a very basic and frequent terrain. Have you ever noticed it? Is it a known bug? Would it be possible to overcome and fix it or maybe patch it (I see the community here is very active and I make use of the TOTPP)?