Only 3 mobs attacking at once.

[Striiker]

I also recall this oddball game mechanic. It took this post to remind me about it. I have vague recollections of this when in Blackburrow and of conversations about it. It's very hazy but it did exist. They would run around near you.. I don't recall if this was done with the intention of spreading out agro across all who get added to the hate list instead of having all mobs pounding one player. It seems to be more of a bug than anything. I do not recall when this behavior was removed from the game.
It's surprising what comes back into memory when reading and discussing old time EQ.