I found that roads I built within City States radius will not cost me money. What's more, even those roads built by me but not within my city radius don't have maintenance cost. However, those roads built by AI but within my city radius will cost me money.
It seems a bug. Because if I assign works to build a lot of roads within city radius of other civilizations, it will cost them huge money and make them bankrupt.
It seems a bug. Because if I assign works to build a lot of roads within city radius of other civilizations, it will cost them huge money and make them bankrupt.