iOS 8.4: after moving audiobooks all titels are gone

After upgrading iPad2 to iOS8.4 all my audiobooks are moved to iBooks

OK, BUT

For all moved audiobooks the 'inner' titels are gone and replaced with titel 1, 2...n

For example you have an audiobook xyz with subtitels these subtitels are replaced with title 1...n

There is no way to track back to the original titel.

If this is intended and not a bug I can throw away all my auudiobooks on the iPad because I NEED the titels!