It's a bad joke on Oasis...
The system menu uses tiny font with huge vertical gaps, and if "Large" is selected in Display options (which does not effect the system menu, it remains the same small sized font), then the Library list view only shows 4 books with extreme gaps...
But with "Standard" size selected, it still only lists 5 books
(if I remember right, even the Paperwhite was able to list 8 books)
Worst upgrade so far...