Signing or editing a book triggers the PlayerEditBookEvent (I've checked), but the new book's BookMeta is not updated correctly. At the very least, setting the book's lore does not work.
Steps to reproduce:
- Use the code below to listen for the event and update lore.
- Sign or save a book (/give @p writable_book -> right click anywhere -> write something and sign/save the book).
- The book should show "Lore Test" below the usual text when hovering over the item, but it doesn't.