Essence of Water not dropping from the goddess halani in act 2 cruel

I am in act 2 cruel, as part of my main quest i am supposed to get the essence of water from the goddess halani by burning her. I defeated the boss and then burnt her, but she didn't drop any essence; i tried quitting the game and playing the mission again and again. Please help, I've tried the same mission like 5 times already and no essence drop. I tried it after a day and it still doesn't work.
What do I do, my character is level 55 , don't tell me i have to delete character and play again :-(

Update : It worked after some tries , sorry for the bug report.