??? Where are you looking?
Because when I look at the:
'Jacket' (generated by Calibre) in the book,
The Info pane,
The Details section in the Library...
Mine are now sorted.
Obviously, I did something builtin to Calibre or a plugin I frequently use, because When I first get some books, they are not always ordered.
Things I regularly use: Polish, Count Pages, Resize Cover (
why would that...), and the Editor (It gets rid / packs more CSS than Polish)