Crashes occur when using Enchanted/Named tools/weapons to knock another player to a falling death

What I expected to happen was...
The player being knocked to their death would die and be able to respawn as usual, death message stating how the player died posted into the server chat as usual.

What actually happened was...:
Player being knocked to their death falls, dies, message displays and server crashes out or kicks everyone playing off of it.

Steps to Reproduce:
1. Use a named enchanted weapon or tool to knock someone from a place high enough to die from the fall.
2. Watch them all to their death
3. See how many people and who get kicked from the server. (most of the time its everyone, sometimes the person who killed using the item is not kicked.