Blacksmith is unable to learn lvl 1 recipe

I just found the "Plan: Apprentice Boots" which states that it can be learned by a level 1 artisan.

I tried to teach it to my completely untrained blacksmith, which is level 1 according to the menu. It said I did not meet the level requirement.

I then trained my blacksmith once (so 20% or so into level 1, towards 2), and now he is able to learn the recipe.

I think he should always have been able to learn the recipe.