I've noticed that there is something weird going on with the pathing of some of the airships in the Port Regal skyway that patrol an area in a group.
Whenver I engage one vessel, the other ships will begin to converge on the ship I am attacking but they won't open fire on me and I am also unable to target them (I get the yellow crossed circle icon).
If I destroy the ship I am attacking, the other ships will hover around the salvage and won't withdraw and if my ship health is yellow when I try to claim the salvage for equipment and gold, the enemy ships will automatically board my vessel.
I have been able to recreate this with the Waponi fleet right outside of Port Regal and the Monquistan squadron at the rear of the zone.