I just noticed that if you purchase a 3 tier recipe, while having an item from Tier 1 in your inventory, at the same time as a tier 2 item that already used it, then it will consume the extra tier 1 tem.
Confusing? Yes, let me try an example.
In building a LifeSteal setup, I purchase a Vampiric Scepter, Rejuvination Bead, and then upgrade to an Emblem of Valour. Now, I have an Emblem of Valour, and purchase another Vampiric Scepter to increase the Lifesteal I have. The problem is, when I decide to upgrade my Emblem of Valour to a Sark's Fervor, it will also consume my second Vampiric Scepter, even though it should no longer be a part of the recipe.
This also happened with a Sapphire Crystal as a prerequisite for Sheen when upgrading to Lich Bane.
Is there any way to fix this or prevent this from occuring?