Steps to reproduce

• Access your admin interface as admin
• Create one draft of a folder and then exit (create a folder, click "Save" button and then exit without publishing the folder)
• Go to "My Drafts" and edit the draft again
  (Open your dev tools)
• Click on "Discard changes"

Here we have a "409 conflict" and the response:

<?xml version="1.0" encoding="UTF-8"?>
<ErrorMessage media-type="application/vnd.ez.api.ErrorMessage+xml"><errorCode>409</errorCode><errorMessage
>Conflict</errorMessage><errorDescription>Argument '$versionInfo' has a bad state: Version is the last
 version of the Content and can not be removed</errorDescription></ErrorMessage>

If we do the same steps, but with a previous published version, then the error do not happen.