Barnacle Breastplate Quest

[klarwa]

In Erudin's Palace, there is a quest from Weligon Steelherder to kill the diseased shark by the docks.

I have the faction and I got the empty shark bag. I killed the diseased shark and got the "shark skin" and then killed the young sharks and got "baby shark remains," but when I try to combine them in the empty shark bag, I get "you cannot combine these items in this bag type." They are not stacked. I can't figure out what is wrong.