I have the same issue. It duplicates the notes while i'm working on them and 30 minutes later I see Evernote made 6 duplicates. I have the feeling that it might have something to do with the preview of the note it shows on the right side and changing the note in a different window (when double clicked). I think this might be the reason Evernote thinks that there are conflicting versions of one note. Though Evernotes doesn't warn about conflicting notes. It just starts duplicating.