Sometimes, a BadMethodCallException arises on Special:ConstraintReport, and sometimes doesn't, even for the same entity. The example below corresponds to Q42.
[WvDWHApAIDAAAEhNrKYAAAAQ] 2018-05-07 22:41:50: Fatal exception of type "BadMethodCallException"
More information from logstash:
Call to a member function getMessageKey() on a non-object (null) /srv/mediawiki/php-1.32.0-wmf.2/extensions/WikibaseQualityConstraints/src/ConstraintCheck/Helper/LoggingHelper.php:107 #0 /srv/mediawiki/php-1.32.0-wmf.2/extensions/WikibaseQualityConstraints/src/ConstraintCheck/DelegatingConstraintChecker.php(595): WikibaseQuality\ConstraintReport\ConstraintCheck\Helper\LoggingHelper->logConstraintCheck(WikibaseQuality\ConstraintReport\ConstraintCheck\Context\MainSnakContext, WikibaseQuality\ConstraintReport\Constraint, WikibaseQuality\ConstraintReport\ConstraintCheck\Result\CheckResult, string, double, string) #1 /srv/mediawiki/php-1.32.0-wmf.2/extensions/WikibaseQualityConstraints/src/ConstraintCheck/DelegatingConstraintChecker.php(447): WikibaseQuality\ConstraintReport\ConstraintCheck\DelegatingConstraintChecker->getCheckResultFor(WikibaseQuality\ConstraintReport\ConstraintCheck\Context\MainSnakContext, WikibaseQuality\ConstraintReport\Constraint) #2 /srv/mediawiki/php-1.32.0-wmf.2/extensions/WikibaseQualityConstraints/src/ConstraintCheck/DelegatingConstraintChecker.php(362): WikibaseQuality\ConstraintReport\ConstraintCheck\DelegatingConstraintChecker->checkConstraintsForMainSnak(Wikibase\DataModel\Entity\Item, Wikibase\DataModel\Statement\Statement, NULL, NULL) #3 /srv/mediawiki/php-1.32.0-wmf.2/extensions/WikibaseQualityConstraints/src/ConstraintCheck/DelegatingConstraintChecker.php(334): WikibaseQuality\ConstraintReport\ConstraintCheck\DelegatingConstraintChecker->checkStatement(Wikibase\DataModel\Entity\Item, Wikibase\DataModel\Statement\Statement, NULL, NULL) #4 /srv/mediawiki/php-1.32.0-wmf.2/extensions/WikibaseQualityConstraints/src/ConstraintCheck/DelegatingConstraintChecker.php(154): WikibaseQuality\ConstraintReport\ConstraintCheck\DelegatingConstraintChecker->checkEveryStatement(Wikibase\DataModel\Entity\Item, NULL, NULL) #5 /srv/mediawiki/php-1.32.0-wmf.2/extensions/WikibaseQualityConstraints/src/Specials/SpecialConstraintReport.php(266): WikibaseQuality\ConstraintReport\ConstraintCheck\DelegatingConstraintChecker->checkAgainstConstraintsOnEntityId(Wikibase\DataModel\Entity\ItemId) #6 /srv/mediawiki/php-1.32.0-wmf.2/includes/specialpage/SpecialPage.php(522): WikibaseQuality\ConstraintReport\Specials\SpecialConstraintReport->execute(string) #7 /srv/mediawiki/php-1.32.0-wmf.2/includes/specialpage/SpecialPageFactory.php(568): SpecialPage->run(string) #8 /srv/mediawiki/php-1.32.0-wmf.2/includes/MediaWiki.php(288): SpecialPageFactory::executePath(Title, RequestContext) #9 /srv/mediawiki/php-1.32.0-wmf.2/includes/MediaWiki.php(861): MediaWiki->performRequest() #10 /srv/mediawiki/php-1.32.0-wmf.2/includes/MediaWiki.php(524): MediaWiki->main() #11 /srv/mediawiki/php-1.32.0-wmf.2/index.php(42): MediaWiki->run() #12 /srv/mediawiki/w/index.php(3): include(string) #13 {main}