Hi,
Thank you for the details, I logged in to check.
On search ID=8 on the advanced options panel you have a date filter active, which excludes all items published before 2000.01.01 – and those two articles were published that day. If you turn it off, it works okay.
For the search ID=9 the post title is the actual post title, not the book title: https://i.imgur.com/hCEfeAH.png
If you want to search the book title, it is probably a custom field. Try selecting “titulo” field or similar, I think it is probably that one.