Following T335971, it appears the extension is saving preferences for temporary users.
Update the code to treat temporary users like anon users.

Wherever these do something different based on whether a user is anonymous or registered, they may need updating (including comments).

Tests and comments should also be updated.

Notes
To help with searching:

In PHP preferences are saved via UserOptionsManager::saveOptions
In JS preferences are saved via methods defined on options.js: https://gerrit.wikimedia.org/g/mediawiki/core/+/809d4c9a9dd2cff6321cdae7a41e75b6c362cbbd/resources/src/mediawiki.api/options.js

Items identified:

• modules/ext.pageTriage.util/models/ext.pageTriage.article.js - change

if ( mw.user.isAnon() || !filterOptionsJson ) { to
if ( !mw.user.isNamed() || !filterOptionsJson ) {

• modules/ext.pageTriage.util/models/ext.pageTriage.article.js - change

if ( !mw.user.isAnon() ) { to
if ( mw.user.isNamed() ) {

• includes/Hooks.php - change

if ( !$user->isRegistered() ) { to
if ( !$user->isNamed() ) {