@Imperfectinfinity
They can easily cover any plothole by either having her reject the light spirit king's blessing or have the dark spirit king return her to normal.
This might be a shot in the dark here but does anyone know if the manga comes with alternate pages for the scenes showing Roxanne's back?
Some of the colored illustrations show her with fur on her back as described in the light novels, an example would be page 4 of chapter 6, labyrinth 2...