Played with Roving Clans, made a privateer army of mercenaries and besieged a city. After a few turns of siege, selected the besieging army, clicked on the besieged city, chose to attack it and wiped them out. After the battle I tried to turn the privateer army back to normal army, but the game did not allow me to do that, stating that the army is currently in siege. Apparently, when you attack a city directly from siege, army still remains in "siege" status. If you, however, first lift the siege and only then attack the city, then everything is fine and you can then turn the privateer army back to normal.

Game version: 1.0.2 S3 (64-bit)