Looks like the page preview just pulls the extract from https://en.wikipedia.org/api/rest_v1/page/summary/{title} - did something go wrong with RB cache purging? Theoretically the reverting edit should've triggered RB to update this extract, theoretically more recent purges of the edited page should've done it too.

I'm not sure about the purges. Sometimes you need a null edit in order to really bypass some caches.

As for the initial cause, there was a single edit (the revert at xx:21). It that purge request was lost (it sometimes happens, are they still being sent through UDP?), the old version could still be presented by some caches (depending on preferences, sometimes only to unlogged users).

Assuming you meant "Page previews", I changed the title of this task.

Also see T226983: Page summary endpoint in RESTBase not updated since about June 27

@mobrovac @Pchelolo Is it possible that the Restbase endpoint is serving an outdated extract" If I remember right it has some caching built-in.

I looked at the page in question and I see it has the correct content matching the wikitext. What could have happened is that the purge request itself fell through, so RB did have the new version stored, but Varnish was serving the old one until it fell out of cache.

@mobrovac can you take this task and push it forward?

Given that the page in question does not exhibit the problem any more, I'm not sure there's something to do here.

@DragonflySixtyseven mentioned in #wikipedia-en on freenode an off-wiki complaint that https://en.wikipedia.org/wiki/Jeddah_Tower had a popup with vandalism in it. That popup showed an old revision of Skyscraper design and construction from 3 days ago that was quickly reverted. I confirmed using the REST API that the old revision was still being used as the summary. I then purged the page (using the UTC purge clock) and re-sent the API request. The API returned the newest revision, which is also what was shown by Popups.

I am not sure if anyone had tried purging the page and the issue is now gone, but the issue was reported at https://en.wikipedia.org/wiki/Wikipedia_talk:In_the_news#Spam. The IP screenshotted and uploaded to imgur, not sure of the reporting rules and norms here, hopefully this is enough information.