These are some bugs I've run into. I haven't been able to play much yet though.
* When my city goes from level 1 to level 2 there are different descriptions of the effect of the Training Yard. The tooltip says +10 accuracy, and the main description says +15 accuracy.
* There are a lot of things that can go missing when you load a previous game. If you sell something, you can keep the new money when reloading as well as the item. Sometimes the border (zone of control) around towns disappear. The border around your units can disappear as well. These bugs seem to be intermittent.
* When shooting a missile in tactical combat, the arrow sometimes does not appear from the shooter, but from the side of the screen. Either left or right. I have an old graphic driver though.
* The last one is not a bug but something that maybe should go into a FAQ. When changing name in My Account here on this site, I can't start the game. It must be the original name. There could be some way around this, but I didn't find it.
I also want to add that the game is fantastic! The mood you create with the quests and the backstory really makes the world come alive.