I was stuck at 174/178 Krytan Explorer….someone posted on another place they went to the Order of Whispers hide-out in the north end of Bloodtide Coast. I had already been there because it was part of my story. I had explored and went into the portal before I ever did the story. I returned and I got credit for it and thought great…but then I went to 174/175 Krytan Explorer??? I went to Harathi Hinterlands where I finally found that I had missed Hidden Ourobon and then the achievement completed.