Frequency: Just once
Class/Level: LVL50 (Synced)
Party or solo: Party
Area and coordinates: The Labyrinth of the Ancients X: 8.2 Y: 16.8
Steps:
1. Play as usual, get to the co-ordinates and it just seems to appear

During a duty roulette run of The Labyrinth of the Ancients, a strange barrier appeared when I was on my way to the first boss. Other people were able to walk through on my screen but I couldn't get past. I was only able to get past when offered to teleport to the boss. Nobody else in the alliance raid seemed to have been able to see it. The barrier was not a boss barrier and was its own thing entirely.