Talk:The Watergod's Altar (quest)/@comment-72.73.68.107-20130825014949/@comment-5166842-20130825015759

It means that one of the slates is still in one of the chests. You forgot to pick it up. In the one-in-a-million chance you've found a glitch in this quest after all this time it doesn't matter, it isn't necessary to complete this quest to keep going through the game.