MediaWiki version: 1.35.0-wmf.5
PHP Warning: [data-update-failed]: A data update callback triggered an exception (Fail-safe exception. Number of ids to be restored is not equal to the number of records that are about to be inserted into master. This should never happen, except for an edge-case that was not detected during development or due to a race-condition that is not covered by this implementation.) [Called from Wikibase\Repo\Content\DataUpdateAdapter::doUpdate in /srv/mediawiki/php-1.35.0-wmf.5/extensions/Wikibase/repo/includes/Content/DataUpdateAdapter.php at line 62]
These are very likely happen because we catch DBErrors which is "extremely discouraged" and can cause transaction inconsistencies and all sorts of issues.