Auto-select selects every item of the listed duplicate groups that can be manually selected without a warning message.
In this case you do have many duplicates, but none of them can be selected without a warning message. Please select the duplicates manually and read the warning to know more about your issue.
As a workaround for users who really know what they do we have an option in Preferences called “Disable item selection warnings”. That will help you out, but use it very carefully (it will still only work with auto select if you check the Allow checkbox).