Hello,
I have the same problem and I know a little more about it.
If you close the application, rename the Adobe folder in documents, DISCONNECT INTERNET CONNECTION, and restart ADE a new folder is created and all the ghost books are gone.
Also if you install the app on your iPhone for example and authorize it with the same Adobe ID you will magically see your old ghost books again.
With these two things in mind I am sure that the books have been synced to Adobe (and that’s what the option in settings is for - but it’s too late now).
The problem is still how to delete them from the Adobe cloud. I could not find a solution and think it is also not okay to sync them without being asked.
Markus
