Wikibase quibble-apitests-only-vendor-php81 tests have been failing since at least Friday, 14 November (#9391 for this change):
php maintenance/run.php CirrusSearch\Maintenance\UpdateSearchIndexConfig --startOver
Updating cluster ...
indexing namespaces...
Fetching server version...opensearch 1.3.20...ok
mw_cirrus_metastore missing, creating new metastore index.
Creating metastore index... mw_cirrus_metastore_first Scanning available plugins...
analysis-hebrew, analysis-icu, analysis-nori, analysis-smartcn, analysis-stempel
analysis-sudachi, analysis-[u]krainian, cirrus-highlighter, ltr, opensearch-analysis-stconvert
opensearch-extra, opensearch-extra-analysis-esperanto, opensearch-extra-analysis-homoglyph, opensearch-extra-analysis-khmer, opensearch-extra-analysis-serbian
opensearch-extra-analysis-slovak, opensearch-extra-analysis-textify, opensearch-extra-analysis-turkish, opensearch-extra-analysis-ukrainian, opensearch-knn
repository-s3
Elastica\Exception\ResponseException from line 178 of /workspace/src/vendor/ruflin/elastica/src/Transport/Http.php: Unknown filter type [truncate_norm] for [truncate_keyword]
#0 /workspace/src/vendor/ruflin/elastica/src/Request.php(183): Elastica\Transport\Http->exec()
#1 /workspace/src/vendor/ruflin/elastica/src/Client.php(545): Elastica\Request->send()
#2 /workspace/src/vendor/ruflin/elastica/src/Index.php(759): Elastica\Client->request()
#3 /workspace/src/extensions/CirrusSearch/includes/MetaStore/MetaStoreIndex.php(213): Elastica\Index->request()
#4 /workspace/src/extensions/CirrusSearch/includes/MetaStore/MetaStoreIndex.php(145): CirrusSearch\MetaStore\MetaStoreIndex->createNewIndex()
#5 /workspace/src/extensions/CirrusSearch/includes/Maintenance/Maintenance.php(238): CirrusSearch\MetaStore\MetaStoreIndex->createIfNecessary()
#6 /workspace/src/extensions/CirrusSearch/maintenance/IndexNamespaces.php(43): CirrusSearch\Maintenance\Maintenance->maybeCreateMetastore()
#7 /workspace/src/extensions/CirrusSearch/maintenance/UpdateSearchIndexConfig.php(69): CirrusSearch\Maintenance\IndexNamespaces->execute()
#8 /workspace/src/maintenance/includes/MaintenanceRunner.php(696): CirrusSearch\Maintenance\UpdateSearchIndexConfig->execute()
#9 /workspace/src/maintenance/run.php(53): MediaWiki\Maintenance\MaintenanceRunner->run()
#10 {main}CirrusSearch: Make keyword fields actual opensearch keyword fields looks like a likely culprit.