Signez posted it before you did—note that the item ID is earlier. The timestamp is later because we re-upped the post; we try to privilege the first submitter when we do that. You can see the original timestamp on https://news.ycombinator.com/submitted?id=Signez and most other pages that list a story. For a detailed description of all this, see https://news.ycombinator.com/item?id=10705926 and the links there.

Better duplicate management is something we're working on. Keep in mind, though, that HN doesn't consider a post a duplicate until the story has had significant discussion. Otherwise too many good stories would go unnoticed.