Nostalrius Begins - Quality wow vanilla realm (1.12)

Hi, so I just spend the last 3 hours on doing the quest chain for the tank trinket Demon's Blood, turns out the 2nd last chain part is bugged ([60+] Uniting the Shattered Amulet), when I attempt to use the "use item" on the ogre in the compound, the item dosn't work, so the mob can't go below 1%. Where should I go with this bug? And any way to get some GM help with this? Seeing that trinket is kinda important to get

Best Regards - Me!