Zombies Spawn In After Creative Player Attacks Them In Hardmode

While on the Hard difficulty, zombies are supposed to spawn in when a zombie is attacked while the player is in Survival. However, I was in Creative mode and attacked a zombie (I was using my fist, later testing showed that you have to be using your fist for this bug), and another zombie spawned in, tracking me (which I also believe is a bug, but is irrelevant because if this bug is fixed then it won't be a problem.).

What I thought would happen was the zombie would die without any zombies spawning in and tracking me because I was in creative.

What really happened is another zombie spawned in and followed me.

Steps to Reproduce:
1. Go into creative mode.
2. Set the difficulty to hard.
3. Set the time to night.
4. Find a zombie.
5. Attack the zombie with your fist.
6. Watch another zombie spawn in and track you.