The updatequerypages cron jobs have a history of breaking ( T113721 , T246063 I'm sure there are others). Usually it takes a while for anyone to notice, probably because the update schedule isn't communicated to users, so they won't know if its broken or just "slow" until they are really out of date.

It would be nice if we could have monitoring for this.

You can get when they were last updated via https://en.wikipedia.org/w/api.php?action=query&list=querypage&qppage=Ancientpages&qplimit=1 (and so on for other page names). The update schedule though can vary for different wikis though. Most of them are supposed to be updated every 3 days, although some of them are only updated once a month. Anyways See https://github.com/wikimedia/puppet/blob/b347052863d4d2e87b37d6c2d9f44f833cfd9dc2/modules/mediawiki/manifests/maintenance/updatequerypages.pp