Trading enchanted book does not consume items and gives ghost book (rare)

I have a Villager with a mending book and some other trades. I can trade all trades perfectly fine and they also restock without problem.

The mending book however only worked till the first lock. After a refill, this mending trade only gives a ghost item that disappears when clicked on, shift clicked, number clicked, opening a GUI, etc

The items to buy it are also not consumed