Since version 1.0.0.290, WorldBuilder.CityManager is nil in gameplay/script context with the base game, which has broken the ability to change plot ownership using WorldBuilder.CityManager():SetPlotOwner(x, y, playerID, CityID)
We can't use plot:SetOwner(playerID, cityID) as then the plot can't be selected to be worked by the city.
This seems to be a bug instead of the expected behavior (for example WorldBuilder functions only available in WB mode) as WorldBuilder.CityManager is still available in gameplay/script context when the Gathering Storm expansion is activated.
See this thread for more details:
https://forums.civfanatics.com/threads/lua-function-not-working-after-update.642369/
We can't use plot:SetOwner(playerID, cityID) as then the plot can't be selected to be worked by the city.
This seems to be a bug instead of the expected behavior (for example WorldBuilder functions only available in WB mode) as WorldBuilder.CityManager is still available in gameplay/script context when the Gathering Storm expansion is activated.
See this thread for more details:
https://forums.civfanatics.com/threads/lua-function-not-working-after-update.642369/