Entities become invisible after death & respawn

Steps to reproduce
1. Create superflat world
2. Summon mob

/summon PigZombie

3. Let mob kill you
4. Respawn and you will not see mob
5. Kill mob

/kill @e[type=!Player]

6. run kill command on player

/kill

7. You will not see drops from previous mob
8. Run testfor to verify they exist

/testfor @e

Video Demo - 15w37a
https://www.youtube.com/watch?v=I_4Ckjcy7kk