Borderlands 2 "friendship rules" achievement not unlocking

Not sure if this is a fault in the game or in the new xbox one OS, but I cannot get this achievement to unlock. The friends I play with unlocked it without issue. I’ve tried removing friends, re-adding them and making them favorites to no avail. Lots of other achievements popped up at once when I downloaded a cloud save from my xbox 360, and I’ve unlocked others since, but this one is being stubborn.