Can't get Ashjra'kamas to level 15

I'm trying to upgrade Ashjra'kamas to 15, but I've got it to 14 and there's no more quests from Wrathion, and no torn pages are dropping! None of the guides mention any extra steps to go from 14 to 15, so any ideas?

I've got all 5 masks, and just got "the most horrific vision of stormwind" so I'm clearing all areas correctly, but without the level 15 cloak I cant get "through the depths of visions" for the mount

Edit: For more info, i'm returning "true" using Wowhead's quest completion for all three "Reconstructing "The Final Truth"" quests