HN search engine now shows Google's 404 error page
hn.algolia.com
hn.algolia.com
Edit: And it's back! Edit 2: And it's gone again!
Remember that a CNAME isn't a redirect or anything, there's literally no way for the receiving webserver to know the domain that was CNAME'd in these sorts of requests.
HN is pretty close to perfect. The only things I'd change are cosmetic (dark mode, better mobile CSS, etc).