Total War: WARHAMMER III

Total War: WARHAMMER III

SFO: Grimhammer III
zhou ming and the bastion
was playing my first real cathey game today (with SFO as always) and noticed the event armies didnt start actively passing through the fallen gates till i had retaken them first. is this because the gates were held by tzeench till i arrived or a necessary aid for the AI? when playing as zhou ming was there actually any value in getting involved in that mess?