Some Recipes don't unlock when I have the necessary items and only unlock when I craft them
(for example I have iron but it wont unlock the recipe for an iron chestplate unless I craft it) this only happens with recipes related to items I had before updating the world in my Inventory
To reproduce the error
1- Create a world in a version prior to 1.12
2- Give yourself some wood or some iron
3- Load that world in 1.12
Edit, I am very sorry for not adding this critical step!

4- switch to a version prior to 1.12, then back to 1.12

You will notice that the recipes won't unlock unless you craft the item itself