When reading https://en.wikipedia.org/wiki/Side-channel_attack, hovering "Meltdown" produces an error saying the summary is not available:
Summaries for other links on the page work fine. I can consistently reproduce this after clearing browser cache, and in Incognito mode, in other browsers, and also after purging the target page from MediaWiki using action=purge.
The Page-Previews code is trying to fetch the summary from the following address https://en.wikipedia.org/api/rest_v1/page/summary/Meltdown_(security_vulnerability) which consistently responds with a 404 Not Found status:
{"type":"https://mediawiki.org/wiki/HyperSwitch/errors/not_found#page_revisions","title":"Not found.","method":"get","detail":"Page was deleted","uri":"/en.wikipedia.org/v1/page/summary/Meltdown_(security_vulnerability)"}
This is happening on January 9th.
Five days earlier, on January 4th, the article was indeed "deleted", as part of a rename.
Before January 4th, the article now named "Meltdown (security vulnerability)" on en.wikipedia.org, was named "Meltdown (security bug)". On January 4th, a redirect existing at "Meltdown (security vulnerability)" was deleted as part of renaming the page from "Meltdown (security bug)" to "Meltdown (security vulnerability)".
It seems that despite 5 fives days having passed, many edits (and therefore purges), as well as manual purges, the summary is still broken.
