#5 - Oct. 26, 2017, 12:54 p.m.
Sounds like you might have abandoned Enchanting at some point and picked it back up again later, would explain the missing recipes you should have from the earlier quests.
Forgotten Formulas of the Broken IslesThis is sold by the Enchanting vendor in Dalaran on the Broken Isles, it will reteach you any quest reward recipes from the Legion profession quests but are currently missing.
Should help you along the way there :)