Hello,
I am a player from WoW Classic Era. I had a Onyxia head, and was on the quest Victory for the Alliance. I was scheduled to drop the buff, but when I went to turn the quest in, a horde rogue came and sapped him. After this, he was stuck in combat and I could not talk or turn in the quest. We had to wait for an hour until I could turn the quest in. I am confident this is a bug, because he never came out of combat even when no hostiles were around him.
I can provide a screenshot, and others were around at the time as well. This occurred at 7/10 5:10PM server time.