As near as I can tell from info in the Libra Eorzea app, there's a point where the Limsa Lominsan main story diverges into two branches (though it's just for a couple quests). Perhaps that's where someone could lose track of it.

The quest Lurkers in the Grotto (Lv 5) unlocks both Further Afield (Lv 6) and Washed Up (Lv 7). Washed Up has a follow-up quest Double Dealing (Lv 8), and then the next quest in the line, Loam Maintenance (Lv 9) requires you to have completed both Further Afield and Double Dealing.


the Limsa Lominsan main story quests (and thier quest givers) start with:

Coming to Limsa Lominsa (Lv 1) Ryssfloh
Close to Home (Lv 1) Baderon
On to Summerford (Lv 4) Baderon
Dressed to Call (Lv 5) Staelwyrn
Lurkers in the Grotto (Lv 5) Staelwyrn

Then, as I mentioned, it branches out a little with:

(branch 1) Further Afield (Lv 6) Gurcant
(branch 2) Washed Up (Lv 7) Staelwyrn
(branch 2) Double Dealing (Lv 8) Staelwyrn

Then the remainder of the Limsa Lominsan main story quests up to getting the airship pass are:

Loam Maintenance (Lv 9) Gurcant
Plowshares to Swords (Lv 9) Pfrewahl
Just Deserts (Lv 9) Staelwyrn
Sky-high (Lv 10) Baderon
Courier for a Day (Lv 10) Wyrkrhit
Thanks a Million (Lv 11) Wyrkrhit
Farmer of Fortune (Lv 11) Lyulf
Relighting the Torch (Lv 11) Fraeloef
On to the Drydocks (Lv 11) H'naanza
Without a Doubt (Lv 12) Ahtbyrm
Righting the Shipwright (Lv 12) Haldbroda
Do Angry Pirates Dream (Lv 13) Ahtbyrm
Victory in Peril (Lv 14) Ghimthota
Men of the Blue Tattoos (Lv 14) Ghimthota
Feint and Strike (Lv 14) Baderon
High Society (Lv 14) Reyner
A Mizzenmast Repast (Lv 14) Baderon
The Lominsan Envoy (Lv 15) Merlwyb