Is this quest bugged does anyone happen to know? I don't know how many times I have killed Neh'Asiir in CoM but the darn diary is NOT dropping.
Only the respawned Neh`Ashiir does drop the diary. The respawned version does get triggered by giving the Engraved Ring to the first version of Neh`Ashiir who will then disapear and respawn. Technically they are two different NPCs that share the same name.