The Gobfather world boss does not give the reward (usually gold) showed in the map. It happens to me with most characters every week. Sorry for my crappy english
This has been going on since undermine was released. It broke all the world bosses so now they will most often NOT give out any rewards to the player. That’s why it takes so long to fill a group to kill them. No one wants to waste their time killing a boss and getting absolutely no reward for doing it.
NOTE: This is not about the quest not completing and needing to move far away and coming back to get it to complete. This is when the quest actually completes and reward nothing.