[Spfamy1]

If you set the font size in Marvin 3 and set the option to apply to all opened books the font gets resized to its default setting when choosing to mark the book "unread".

This may not seem like a bug but when you consider it's possible to mark a book "unread" and still want the font sized correctly on that book this way the book thumbnail cover doesn't mess up the reading queue in the home screen - then this in my opinion should be considered a bug.