Zombified piglins don't aggro newly spawned piglins

The bug

Newly spawned piglins will not become aggro when you attack a piglin that is already argro towards you.

How to reproduce:

1. Make a pen and single out a piglin
2. Hit the lone piglin
3. Kill the others 
4. Spawn new piglins 
5. Hit the lone piglin again 
6. Go in with new piglin and they wont attack you.