Well today is the first time I got double interdicted; or rather, interdicted, and then ganged up on.
The mission pirate I expected, and frankly they're good money and mats so I just drop out of supercruise the moment they interdict and then blow them up.
What I did not expect was some random trash talk from another pirate who wasn't related to the mission, who then bamfed in during the fight with the first guy.
I mean, obviously I clobbered them both and looted double mats, because you don't just interdict a cutter and live, but it was interesting AI behaviour that I've not seen before