Hi folks!
I need advice on a problem I haven't been able to solve for a long time.
I've got EPUB 2 as well as EPUB 3 (differs by publisher) files in my Calibre library.
In there, I edit metadata, embed, polish x2, and save, then I use iTunes to drop the files to my iPad's Marvin 3 reader app.
OK, now here's the problem:
Once I finish editing metadata in Calibre and load the files in the Marvin app, nothing wrong with EPUB 2 metadata, but when it comes to EPUB 3... 
Marvin won't show the new metadata in EPUB 3.
To be exact:
Title - shows as edited
Title sort - shows as edited
Author - shows as edited most of the time (sometimes the field lists illustrator, translator, editor, etc. - which I don't need)
Author sort - not correct, shows as 'Name Last Name' but should be 'Last Name, Name'
Series and number - is EMPTY!!! (especially important field to me)
So WHAT exactly should I do so those Author Sort / Series and Number show up as they should?
If possible, write me the exact steps I should make.
...I have Sigil installed if necessary. Though, I'm a total Sigil beginner.
*Polishing I use (selected options):
Polish - update metadata in book files; update the cover; remove a previously inserted book jacket
Modify e-pub - strip Kobo DRM remnants; remove all metadata jackets; update metadata; remove non dc: metadata elements