Byzantium’s AI does not build the fifth water cistern and thus loses part of the bonus.
I also noticed that the AI builds 4 only when the AI has built Cistern of the First Hill .And when AI does not build Cistern of the First Hill, AI always has 3 cisterns by default.
I noticed that the Byzantine AI is not using the Triumph ability in Imperial Hippodrome. Also the AI does not use the Varangian Guard (Berserking) ability and the Cataphracts Charge ability the AI does not use either. Limitanei also does not put a wall of shields .
AI also doesn’t use Arkitoi Defense when enemies destroy villagers near Cistern.
Varangian Guard don’t use Transport Ship.