Enderman can still teleporting after been killed.
How to Reproduce:
- summon a Enderman.
- set the game mode to default. (not necessary, but this can improve the probability of teleporting)
- Kill it closely.
- If the Enderman doesn't teleporting, try again.
You'll find that some Endermans teleported to another position, althouth their health was 0.
In my opinion, dying Enderman shouldn't teleporting, because they are already died.
MCPE-19544 Endermen can teleport away during death animation