Units no longer path through siege towers. When you dock them on a wall, the unit that used them will immediately climb down and vacate the tower and the siege tower will be treated as basically non-existant.
This makes sieges absolutely unplayable and with it about the entire game since you practically can't play any siege assaults.
This bug needs to be fixed ASAP. I see no sense or need in playing the game any further as long as this bug persists.
Discovered during my East-Anglia campaign while laying siege to Stamford.