This systemd timer runs every minute, but the last time it succeeded was Dec 7, 19:41 UTC. Since then it's been failing consistently; journalctl looks like:
Dec 08 16:52:00 mwmaint1002 systemd[1]: Started MediaWiki periodic job wikidata-updateQueryServiceLag. Dec 08 16:52:01 mwmaint1002 mediawiki_job_wikidata-updateQueryServiceLag[131972]: Failed to get lag from prometheus Dec 08 16:52:01 mwmaint1002 systemd[1]: mediawiki_job_wikidata-updateQueryServiceLag.service: Main process exited, code=exited, status=1/FAILURE Dec 08 16:52:01 mwmaint1002 systemd[1]: mediawiki_job_wikidata-updateQueryServiceLag.service: Unit entered failed state. Dec 08 16:52:01 mwmaint1002 systemd[1]: mediawiki_job_wikidata-updateQueryServiceLag.service: Failed with result 'exit-code'.
SAL shows @RKemper was reimaging WDQS hosts at the time it started failing, not sure if that's related or coincidence.