I was hooked into it too, until I found this fix in the B&N Nook thread....post #64
https://www.mobileread.com/forums/sho...75#post1260075
What it amounts to is all you have to do is go into Calibre's preferences, click on "saving books to devices button, add "My Files/Books/" to the template pathway so that it reads
My Files/Books/{author_sort}/{title}/{title} - {authors}
and then all I have to do is just reconvert the books epub-to-epub and that works like a charm for me. I have used this now on many books with no problems at all. No more rigamarole of having to adjust the opf files or copy/add jpg files.
Go figure...