The quest worked fine for me once I figured out how to do it. The text is poorly written and it apparently coincides with a different Grummle escort quest that appears to fit the text better… which makes it all very confusing.
If you head roughly NW from the quest giver, immediately down the hill you can see red yells of help from a group of 5 Grummles carrying packs and leading yaks who need defended. They are following the path in the direction of the Dooker Dome, where you were erroneously told you need to take 5 Grummles. I mistakenly escorted these guys, right by the Dooker Dome, 3 times before realizing the reason I was getting no credit for it was that they were the wrong Grummles. I mistakenly kept assuming that the reason we weren't finding goods was that I only managed to defend 3 of them on my own. They're attacked by a lot of Hozen, repeatedly, which seem to be coming from the Dooker Dome. Again, confusing.
Here're the corrected instructions:
1) GO TO THE DOOKER DOME, exactly as the quest says. You DO NOT take any Grummles with you to the Dooker Dome, unlike the Quest says.
2) As soon as you arrive at the Dooker Dome, 5 Grummles with no packs will leap out of hiding and follow you. Lead them around. Unlike what the quest says, you DO NOT have to DEFEND THEM or even pay attention to them. As soon as a battle starts, they all hiding in the surroundings like ninjas. (This is really helpful, actually.) They come out of hiding and follow you again as soon as the battle is finished.
3) When you find the goods, unlike what the text says, the Grummles don't know what to do with them. You have to "explore" it first by clicking on it and waiting a bit. Perhaps you are checking for traps for them? Then one of them walks up, straps it to his back like a pack and runs off on his own. UNLIKE WHAT THE TEXT SAYS, you still DON'T have to DEFEND him, follow him, or anything. Just let him go.
Once I got all this figured out, it was actually a fun quest and leads you right up to meeting the two quest givers and freeing the second Yeti. It was all the misdirection that I had to battle through - repeatedly - that really doesn't fit under any definition of either 'fun' or 'interesting' that I am aware of. In multiple languages.