The purple item "Art of War" needs 2 sage wands to be made.
The orange item "Book of Mysteries" needs 2 sage wands, a crystal staff and a clasp of life.
There is no reason for the recipe to not include the Art of War instead of the 2 sage wands. Only thing the current recipe does is induce some mild annoyance/fury when you get one from a chest or a CoF run.
If you know any other similar cases please write them below.