Zombie Pigmen Counterattack!

Play on Realm server
I accidentally attacked Zombie Pigman at Nether.
When I set the time to release the hostile, I was relieved that the hostile action was canceled or scattered away.
after that when they A few pigs who changed suddenly from herd of Piggman will attack with a dash.
Moreover, many times!
Changing difficulty level to Realm server administrator
Normal>PEACE>Normal
Did it end?
NO!
Zombie pigs counterattack again!
It is continuing now...