Game Mechanics: Mobs losing aggro far away

[Rairun]

I played from 1999 to 2001. I recall that in Classic zones, mobs would never stop chasing you, ever. But when Kunark was released, I could aggro a spider in FV and run away with SoW, and it would eventually stop chasing me. However, if I ever approached it again, it would instantly run after me.

I remember fighting a Sarnak in LoIO, running out of mana and then fleeing. I meditated to 100% and decided to hunt some tigers away from the fort. Half an hour later, I thought I'd try a couple of Sarnaks again. As soon as a I approached the fort, dozens of Sarnaks came after me, because that one original Sarnak had gone back to the fort and spread the aggro.