[Manichean]

Originally Posted by TMF

I've reported this as an error, Ticket #7356 (#http://bugs.calibre-ebook.com/ticket/7356). I can confirm that reconversion from EPUB to EPUB in Calibre works as a workaround.

Wait, you have problems with ePubs you download from the net, correct them using Calibre and report that as a bug? You might want to report to the publishers instead that their book isn't working with iTunes.
In short, if I understood correctly what this thread is about, that is no Calibre bug and the ticket is, well, very out of place.