it's happened couple times, Bosses with shield that need to break be killing the add's.
They got bugged, when the add's respownds you try to hit them, they are just disappeared.
and you cant break the shield, Lord Of Ferea you can reset be leaving the boss area. but Lord Silvester you cant reset like that.
its 3'd day that Lord Silvester is bugged.
Im not mad at all, just no loot, and ofc no one care about it.
1.
Bug2.jpg
2.
Bug 3.jpg

Notice:
Goblin will be happy to earn jewel of chaos.

Thanks, Good Luck, Have Fun.