I did some checking and didn't realize that Calibre also sets the CDEContent value in metadata. As part of the sync process, this metadat point, 501, needs to be set to EBOK. I used to use Mobi2Mobi to add the ASIN and CDEContent tags, but since tey are both in Calibre, I can just run a conversion, even mobi to mobi, and those points will be added.
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