Japan took a city from me (Kerma in the south) and in peace negotiations I had them give it back to me. When I get it back, the game asks me if I'd like to keep or destroy it (the latter is greyed out). If I choose to keep it, it will count as occupied. So it doesn't grow.
In the savegame, ask for peace with Japan and then have them return Kerma.
In the savegame, ask for peace with Japan and then have them return Kerma.