|I sometime make HN submissions. If the URL has already been submitted by another user, I am taken to the existing submission page, and I think the submission might also get an automatic upvote from me.|
Today, I tried to submit a story and got a message:
"Sorry, that story was previously submitted."
I couldn't find any previous submission via hn.algolia.com, and it seems a few other folks have asked about this in the past, without any answer:
I hadn't previously submitted the same URL or any URL from the same domain.
The URL returned after submitting the form included 'deaddupe', which offers a clue, but it would be great to know for sure what causes this.