It's the same story. It doesn't make sense to have two threads about the same story on the front page at the same time. Not only does that split the discussion, it takes up an extra front page slot, and those are the scarcest resource on HN (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...).

The salient question is whether the two submissions would lead to substantially different threads. If not, then we treat them as dupes, even if they're different articles.