From Cultist O -
A while ago I mentioned an error when I break an Ender Crystal, here is the full report [snip]

[trying new build] ok, now I am getting:

[INFO][OtherDrops:2.8b.156] EntityDamageEvent: tool is null, please inform developer.

But it only seems to happen when I shoot it with an arrow. I've confirmed that it happens with or without enchantments and lore text

Edit: It also happens with TNT explosions, but not my fist or a sword