I’m not sure if this is a bug or an oversight based on how quickly we’re leveling with the XP buff, but after you finish the Demon Hunter area and are teleported to Orgrimmar, the next quest is marked as Low Level, and won’t appear on the minimap, nor will the ! appear above Khadgar (unless you’re tracking low level quests).
Minor issue but I did fly around a little at first trying to make the quest trigger, not realising it was flagged for low level (which I wasn’t tracking, by default). I only found it when I decided to try talking to Khadgar just for the heck of it. The subsequent quests are also all flagged as low level.