Bugged Twilight Corrupter

[Caapo]

Hi we killed yesterday Twilight Corrupter for quest The Nightmare's Corruption, but he did not respawned, it's already 10 hours and a lot of guys in my guild wants it. What's the respawn time? 

[Burning]

Hello,

The Twilight Corrupter triggers by having the quest and walking into his area, try to leave [The Twilight Grove] and come back after.