Specifically, this one request is taking over a minute and blocks rendering of the page:
https://www.mediawiki.org/w/load.php?debug=false&lang=en&modules=ext.echo.badgeicons%7Cext.echo.styles.badge%7Cext.uls.pt%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cmediawiki.legacy.commonPrint%2Cshared%7Cmediawiki.sectionAnchor%7Cmediawiki.skinning.interface%7Cskins.vector.styles%7Cskins.vector.styles.experimental.print&only=styles&skin=vector

server:mw1270.eqiad.wmnet

The issue went away after being observed for multiple times (because it got cached?).

Logstash doesn't show anything useful for host: mw1270 AND wiki:mediawikiwiki