Mobs not responsive after player death

Video link demonstrating the problem with Pigmen

What started as the thought that Zombie Pigmen were bugged - appears that all mobs are affected.
1. Mobs you hit before death, cannot be hit after you respawn.
2. "Grudge" mobs like Pigmen will not remain hostile to you after you die.
3. Pigmen will not group-attack you after you die and re-initiate a fight.

Steps to reproduce

• Set your spawn
• Spawn a group of Mobs (Pigmen, Zombie, Skeletons, Cows, etc)
• Hit each one without killing them, then die. (If you choose Pigmen, they will gang up on you)
• Upon player respawn, you can no longer hit the mobs you previous attacked.
• Pigmen become neutral
• Eventually after a delay, and some luck you will be able make contact, but if you'v hit Pigmen, the group will no longer attack you