Illidan didn’t drop loot for me this week. Not even a postmaster over half an hour after the fact.
It’s a known bug if you kill illidan with a DOT or a bleed you don’t get loot.
It’s been a bug since the original burning crusade fight so about 17 years that bugs been there.
Blizzard hasn’t done anything about it.
You’re going to have to call a support ticket in and then fight three or four times because they’re going to claim that you didn’t kill him even though you’re locked to it