MediaWiki internal error. Original exception: [XfhsPQpAADwAAJ22fjYAAAAN] 2019-12-17 05:48:45: Fatal exception of type "Wikimedia\Rdbms\DBQueryError" Exception caught inside exception handler. Set $wgShowExceptionDetails = true; at the bottom of LocalSettings.php to show detailed debugging information.
Trying to use filtering of registered users following T238483: Special:NewPages - allow hiding pages created by users when non-users can create talk pages
Can be reproduced by following the same link - consistently returns an error
A bit of testing reveals that there is generally an error when attempting to use associated namespaces (eg https://en.wikipedia.org/wiki/Special:NewPages?namespace=2&invert=&associated=1&limit=100)