Wrong note duplicate recognition at import

I export 787 notes via xml and reimported to a fresh database. I receive a message that there is one duplicate and 787 are imported.

As a test i also import the same original db into the new db. I now have a message that 6 messages are imported and 781 are duplicates.

I had vaccumed the original db before any exporting or importing. I also checked the original db with sql lite administrator and exported the results there to xml and xls. It appears that cinta misses cotitle and c0text field which have the same content.
BTW I had the same problem previously with incorrect duplicates when i amalgated mirroring databases.
(http://cintanotes.com/forum/viewtopic.php?f=6&t=1147)