Hmm, now that I think about it, the DeDRM plugin (which uses WINE to decrypt EPUB/PDF via Adobe Digital Editions) is probably responsible.
It is probably calling WINE in order to attempt to run the key extraction code.
But in that case, it should be triggering on EPUBs as well.
...
AFAIK, the plugin tries DeDRMing all imported AZW*/EPUB/PDF whether they need it or not.
