If you’re trying to do the Elune’s Blessing quest to kill Omen in Moonglade it’s currently very buggy. The quest is traditionally completed by standing in the light that appears on Omen’s corpse (regardless of if you tagged/killed omen), but that isn’t working.
Anyway the solution is to stand in the light and spam-offclick the +10% Stats buff the light gives you, over and over until you get quest credit.
It took me about 120 tries, other guildies and pugs got it in ~20 ~40. Keep at it and good luck!