The Fourth Fragment bugged?

Is the quest “The Fourth Fragment” bugged? I have killed the Ymirish Chieftain 4 times and the fragment doesn’t drop. I also checked the camp he was in but I didn’t see anything that could be picked up or opened.

We did that a few month back now and it worked correctly. i cannot remember exactly, but it’s either a specific boss giving it, or a box that you need to pick up.