If I hit a pigman in the overworld they want to kill me in both worlds.

What I expected to happen was...:
to be able to hit the pigman in the overworld and go to the nether without being attacked.

What actually happened was...:
If I hit a pigman in the over world and went to the nether I would be attacked.

Steps to Reproduce:
1. go in survival
2. make a nether portal
3. let a pigman go through the portal in the nether
4. attack it
5. then let it go back
6. then go to the nether