I got the recipe from SE P1 years ago... the first time I ran the dungeon. Tazza is the one who drops it. I do SE p1 at least 3 days a weeks for years and have no got it to drop again. Kaeyi has nothing to do with it dropping. I also I emailed Anet a few months ago about the SE p2 recipe. They ANET told me it still drops from the last boss. Hope this helps.