I have an ePub that fully validates using ePubCheck 1.2. FlightCrew doesn't like it.
FlightCrew is telling me that my font declaration is incorrect when FlightCrew says it's fine.
The <item> element's "media-type" attribute has value "font/opentype", but the file's media type is "application/vnd.ms-opentype".
That is what FlightCrew says is incorrect when it's actually correct.