Both Priest ability Divine Vision and the Sorceror King will present dialog options for the player to be rewarded with a crafting recipe.  It appears eligible recipes are from a small list of basic recipes, as the rewards stopped adding any recipes around turn 50 in my game (even though I'm missing chain mail boots for instance) -- this is despite the fact i'm occasionally finding recipes from chests.

Thus, by mid game this turns into a non-reward option.  If no more recipes are eligible to be rewarded, the dialog shouldn't include that option.  Or it may be a bug that I'm no longer being rewarded with recipies.