Originally Posted by crutledge
After checking with Kovid and sending him both the Sigil file and the Caliber file I received the following answer:
Quote from Kovid
"The problem is that the sigil file doesn't identify the cover as a cover. There needs to be a guide element in the OPF file. Compare it with the OPF from the calibre epub. "
I'd also like to see both of these files for myself. Create an issue on the tracker and then attach the epubs.