Pigmen permently aggro'd

There is a serious bug in the Nether. i wish i could record whats happening. 2 days ago the pigmen was aggro'd for no reason. i did submit a post for this. well today i try again. i stand at the portal in the nether end. there is about 10ish pigmen around the portal. a couple even walk near me. no problem. i get my confidence up as i'm wearing all my best kit as i'm after wither skulls and walk about 10 steps into the nether. they all go crazy. i didn't even have a weapon in my hand. please fix this. it not nice getting knocked back into a lava lake and losing everything. mift.