Because of a quirk in the old MLA Citations format, the conversion to the new unified format resulted in incorrect citations for all Types except Journal Article and Edited Book. I've uploaded a fixed MLA format to our ftp site, and it will be included in a silent update (and of course future updates). If you use MlA and can't access our ftp site, you can write to me and I'll send it to you as an attachment. The format should be put in the folder
~/Library/Application Support/Bookends/Formats
(if you're using Lion or Mountain Lion, to get to your Library folder hold down the Option key and click on the Go menu in the Finder).
Jon
Sonny Software