Possible Bug: Headless Fish Killer Chiefs

[Wids]

So by now it has happened three times on three different dungeon delves into the Fish Killers' lair (or "Gray Wilds - Bugbear Lair" by its actual map name) with three of my characters (Falteine, Maralah and Barleigh, if it matters).  You know how you kill one of the goblinoid chiefs and check his lootable corpse, and in his inventory are the following?

1)  A specific amount of Gold, somewhere in the hundreds.
2)  A head for you to take back to Mayor Felishar.
3)  Some random junk item.

The Fish Killer Bugbear Chief doesn't have any Fish Killer Chief Head in his inventory.  No head, no proof of the kill, no reward from Mayor Felishar.  

Is this a glitch, is it something that got overlooked, or is it somehow working as intended?  

Thank you.  

[kalbaern]

The reward is mainly for goblins north of Orlbar. No head here was originally intentional.