This quest comes up when you bring up the Dragon Isles reputation summary (off the mini-map) if you haven't yet done the starting quests for Zaralek Cavern. It will tell you "Complete the quest Smells Like Loamm near Loamm in Zaralek Cavern". I found, on an alt, that I could go into Zaralek Cavern and do daily quests on an alt even though I didn't have the quests to go into the cavern. And this quest did not show up when I went to the correct location to pick it up.
If you have this showing on your Dragon Isles reputation summary as a requirement, it's because you have to unlock The Land Beneath. And, in order to unlock it, you need to have finished chapter 1 in The Forbidden Reach. I could not find anything saying that you had to have something finished in The Forbidden Reach before getting the quest to go into Zaralek Cavern. In fact, all of the 10.1 notes indicate that all of your characters should get the "The Land Beneath" upon logging in after 10.1 goes live.
I got very worried that I wasn't getting credit for Loamm Niffen reputation on my alt because this reputation showed as "Faction Locked". However, I did get faction reputation rewards from the reputation guy in Loamm, even though the Dragon Isles reputation summary showed the faction as locked.