It has been a while since I've done these reps, but wasn't it random which dailies were up each day? I recall it switching and sometimes you would have to go up to Kun Lai for one rep while other days you would have to go to Krasasong for another rep and still other days you would have to go to Jade Forst for yet another rep. So that is my guess. That you had a lucky 3 day streak of it being AC rep, but that really it is still random which rep dailies are up each day.
Edit: Did a little wowhead searching and it seems my recollection is only partly right. While the quest hubs do rotate, it is always AC rep and the leader quests all come from that same Sage. So then no... I have no clue why that NPC has stopped interacting with you. Sorry.
Edit: Did a little wowhead searching and it seems my recollection is only partly right. While the quest hubs do rotate, it is always AC rep and the leader quests all come from that same Sage. So then no... I have no clue why that NPC has stopped interacting with you. Sorry.