The NPC has been bugged standing @Gladefall Run since yesterday, and nobody is able to interact with him (Several people have passed by but no luck)
He is needed since the Bird Whistle item can only be bought from him and is required to complete the skyscale collection achievement, therefore unlocking the mount.
There is no event related to him going on, and so far I've not found, or been able to find an other instance of the map to see if I could interact with him there. The daily reset has not done anything either.
Is there a known workaround, or do we really have to wait for a patch of the game ? Which is in 3 weeks afaik (I've seen this being said on other similar posts regarding this type of issue. Map resets coincide with patches? ...)