For example, if you search "It's a common misconception that Bitcoin is a safe haven" it will return this result, and list it as 6 days old. https://news.ycombinator.com/item?id=22558517
If you change the search scope to "the last month" the result disappears. Adding site:news.ycombinator.com does not help.
Duckduckgo and Bing both exhibit the same symptom. Yandex does not even return a result for the search.
The help link of the HN search is a bit hidden. Click 'settings' on the top right of https://hn.algolia.com/ first, then the link is in the footer.