I have set the world's gamerule doMobSpawning to false.
Attacking spawned Zombies or Zombie pigmen in the overworld causes zombies to spawn, using the new mechanic, and attack me.
This is true for both creative and survival.
Linked issues
Comments 2
Duplicate of MC-14722, please use the search function to see if your bug has already been submitted. Currently over 55% of tickets are being closed as duplicate.
I am experiencing this as well. Hitting zombie pigmen while in the nether causes regular zombies to spawn.