bugged quest? (Anything You Can Do)

To complete this you need to do the dungeon Sepulchre of Dragrimmar and kill the last boss Fragment of Antiquites. But when I do so I only complete the dungeon quest and it doesnt update Anything You Can Do

The Fragment of Antiquities is a boss on the first level, not the last boss. The last boss is the Remnant of Antiquities. It's very possible to accidentally avoid the Fragment of Antiquities while going through the dungeon. He's in the very upper-left corner of the first level, an area you don't necessarily need to fight to in order to descend.

I see -.- haha, thanks for the help <3

No problem - made the same mistake first time I did the quest, too.