I had expected the enchanting system to function normally and provide me with a series of enchantments as it always does.

I had enchanted the book for 30 levels of experience for I do quite enjoy feather falling IV books. The book I had retrieved had three enchantment on it as followed: enchantment.null III, feather falling IV, looting III. To my understanding "enchantment.null" should not be there.

I will try to best explain what realm in the game I was in, and what I was doing.
I was in the End realm at my Endermen farm gaining experience whilst going back in forth enchanting my items at the enchanting area I had placed. Upon enchanting a book for what appeared to be feather falling IV I had also received two other enchantments one of those being enchantment.nulll II, and the other being looting III on on the same book.