I equipped a Livingwood Avatar with the Rod of the Unstable Reservoir and supplied the avatar with mana using a mana pool and basic mana spreader (no lenses). Whenever said Livingwood Avatar kills a mob that has been given a nametag, my game crashes.

FML log: https://gist.github.com/anonymous/b9c38477d6a89d320d81

I can recreate this issue by using a nametag on any hostile mob within range of the Livingwood Avatar. My game also crashes if the named mob was created using a named spawn egg. Only when the avatar kills the mob does my game crash. If the avatar is disabled before the mob's health is brought to zero, the game continues to run with no hitches. I have not attempted to recreate this issue with named boss mobs such as the Wither Boss, Enderdragon, and the Gaia Guardian.

Also, for what it's worth, I tested killing named mobs with the Rod of the Unstable Reservoir myself, Livingwood Avatars equipped with the Rod of the Hells, Botania Bellethorn flowers, Thaumcraft golems, Extra Utilities spikes, and Pneumaticcraft turrets and received an appropriate chat message saying the named mob was killed and no crash occurred.