Hi. I just played MC after a long time again and can confirm this is an issue. It's not "Resolved" as the bug status tells. My experience I had today: I hit a pigman and it of course triggered an endless onslaught of zombie pigmen which is normal. They funneled into some trap and I killed them all but they just kept spawning (which is OK). Then I ran away and they chased me all the way to the nether portal. When I went back to the nether, managed to fight them off until there was a 3 minute silence with pigmen spawning around me in the distance (longer than the 40 second cooldown). When I moved around, the newly spawned still attacked me. Maybe some were aggressive on higher structures because pigmen were falling to their deaths: these can pass their aggression onto others too.
Eventually after 30 minutes of fighting I had enough and switched to peaceful & creative mode and then back to hard and survival. Of course, they despawn and respawn, but even after this they attack me after some time! I flew back to the point where I hit the first pigman and along the way they were even agressive to me in creative.
I don't know much about game programming, but I think the anger data should be attributed to the player, not the chunks from which I can tell happens here. So when you run into a new chuck with anger you trigger mobs but when you fought off some mobs in a stationary position and this anger becomes zero and no mobs are triggered. Maybe also fix the issue of mobs behind walls triggering new mobs. But that's just me telling what genius level programmers should do lol. xD
Edit:
@@unknown Same issue here with the zombies not in the line of sight. I had pigmen fall to almost their deaths (20 blocks) from structures above mine in the nether. I can't kill these pigmen. So when I kill all pigmen near me, when I move around, these pigmen that are higher than I am might follow me around and spread their anger into new chunks.
@Johnibur Then I just have to wait I guess instead of finding a mod. ;D
Would be nice if there was some kind of cool down bar much like when you see during a raid. When this disappears it means you're free to wander