Steps to Reproduce:
1. Place a nether portal in the overworld
2. Wait until one or some zombified piglins naturally spawn in the overworld
3. Find a piglin in the nether and make it go to the overworld through the nether portal
4. Wait until the piglin is zombified and hit it

What I expected to happen was...:
The natural spawned zombified piglins will assist the zombified piglin converted from piglins

What actually happened was...:
The natural spawned zombified piglins don't do anything