So it's not really a flag, it's that the algorithm that determines who the monsters attacks had a bug. The bug made it so that when there were a group of players to choose from, the mob would always pick players whose (hashed) identifier was higher on the list. Since the hash of your ID doesn't change, those players would always get picked on first. Like if your name is Aaron A. Aardvark, you're always coming first on any alphabetized list.
But it wouldn't always pick them, it would pick them with a higher probability that also depended on the players' relative distances to the monster.
So it's a stochastic bug where any given occurrence can be explained as "you just have confirmation bias, you don't notice all the times Zygy Zebra gets attacked" or "you must have been closer than Zygy even though you thought you were a bit further away". Especially if the game has a first-player perspective which makes it harder to estimate whether you or another player is closer.
