Zombie pigmans do not "forget" the player.

i was at the nether and accidentally hit a pigman, every pigman at the nether started to chase me even far ones as soon as i got close enough for them to see me, (they were not close to me when i hit the pigman before) even leaving the nether and coming back doesn't help, every time i go to the nether now every pigman in there come right at me without me even doing anything.
logging out and back in doesn't help either
please fix this....