Not a bug. Farm buildings require Xeno Farming. Technically your initial colony *has* basic farms, which is what allows you to grow your population to 8 billion in the first place. In general, you don't want to put Farms on Farm Bonus tiles unless there's at least one Approval tile there as well, because growing your population also drastically reduces your approval rating, and as you upgrade the farms, they will soon provide far more population than you can please, since the more people you have, the less effect Approval buildings have. You definitely, definitely do not want to put a farm on your homeworld, since it already has a double pop cap. As a rule, one farm per planet. You want to keep your approval rating high because it increases birthrates, which means more taxpayers, sooner. If it's at 100%, you get double birthrates. This does not have to be universal approval--just 100% on a planet will increase that planet's birthrates, and if you are a Super Breeder, you get eight times normal birthrates.
Don't improve those first few colonies until you can afford it. Buildings cost a lot of money, and you can't turn them off with a slider. If you build any early improvements on your planets, make them Econ buildings.
One thing I always do that always seems to work is research Trade right away. Research trade, then sell it to everyone you meet. They will send Freighters to your worlds, which gives both of you a lot of bc per turn, and of course, you can send your own freighters wherever you want, the farther the better. Trade is, in many ways, better than taxation, especially if you get the U.P. vote to remove restrictions, which doubles Trade income. At one point, I had Master Trade, the U.P. voted to remove restrictions, I had 7 trade routes going, my Taxes were at 5%, global approval was 100%, and I was still making 3000 bc a turn with a HUGE army. It was like having an endless Economic Boom event.
If you get the above, however, do not go Evil. The U.P. also has a vote to restrict Evil trade. This happened to me. I recovered from it, but it's just not the same.