Sharing is I did discover I had duplicated my own work in one hub into another hub. Yes, the first was original to me and yes I repeated my own personal work, however the 'web or internet' governed by web browser sees that mechanically as a duplication of content.
Also, I realized once I had republished something I had long forgot I had published. With a little work discovered I had published a poem I tried to publish at Hubpages some ten years earlie at a chat site I was frequently. That poem still resided at that chat site, therefore I was duplicating an original published work.I am not sure if that helps or not, though those two were from personal experience.