You've been tricked by the re-up mechanism. If you mouse-over the times on both articles you'll find the other post is older than this (by 45m). But you can also use the incrementing ID in the URL to figure out which is older.

Just to add to gnabgib's (correct) explanation:

It's an artifact of HN's re-upping system, described at https://news.ycombinator.com/item?id=26998308 and links back from there. About the timestamps, there are past explanations here: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que....

Sorry for the confusion—I know it's weird but the alternative turns out to be even more confusing and we've never figured out how to square that circle!

The relativized timestamps only appear on the frontpage and /item pages, so you can always go to links like https://news.ycombinator.com/submitted?id=lairv or https://news.ycombinator.com/from?site=anthropic.com to see the absolute order.