Missing Knowledge : The Three Legendary Blacksmiths of Mediah

Player name : WOWBIGTIS
Family name : SuckmyDik

Bug Name:

Missing Knowledge : The Three Legendary Blacksmiths of Mediah​

Bug Description:

I have already done mission (Altinova, the Land of Blacksmiths) but i cant get knowledge : The Three Legendary Blacksmiths of Mediah.
now my season pass stuck in (The Legendary Blacksmiths?! Complete the [Suggested] [Lv. 51] Mediah: The Legendary Blacksmith questline or listen to the Black Spirit’s explanation)​

How to reproduce/proof:

please help me to fix it, thx a lot​

 

If you do complete the Altinova, the Land of Blacksmiths quest.
But not get The Three Legendary Blacksmiths of Mediah knowledge.
Try talking to Tulem, maybe can get .