Not the first time.
Back when Cygnea/Enshar was introduced there was an instance that only members of the legion that held one of the camps could enter.
Also, most of the Legion quests and content in Demaha is restricted to the larger older legions. You have to be legion level 5 or above to even acquire the quests. Newer legions (ones created after 6.0) can't access this content because the bosses and instances to complete the Legion Tasks don't exist anymore and were never updated.