@Multichill reports the following error when visiting https://www.wikidata.org/w/index.php?title=Q9334&diff=prev&oldid=613729134&unhide=1:
[WnI3eApAMFIAAH@GeXUAAAAE] 2018-01-31 21:39:04: Fatal exception of type "BadMethodCallException"
From logstash: https://logstash.wikimedia.org/app/kibana#/doc/logstash-*/logstash-2018.01.31/mediawiki?id=AWFORHjcqJPajYV1M55X&_g=()
#0 /srv/mediawiki/php-1.31.0-wmf.17/includes/diff/DifferenceEngine.php(629): Wikibase\Repo\Diff\EntityContentDiffView->getParserOutput(WikiPage, Revision)
#1 /srv/mediawiki/php-1.31.0-wmf.17/includes/diff/DifferenceEngine.php(480): DifferenceEngine->renderNewRevision()
#2 /srv/mediawiki/php-1.31.0-wmf.17/includes/page/Article.php(730): DifferenceEngine->showDiffPage(boolean)
#3 /srv/mediawiki/php-1.31.0-wmf.17/includes/page/Article.php(464): Article->showDiffPage()
#4 /srv/mediawiki/php-1.31.0-wmf.17/extensions/Wikibase/repo/includes/Actions/ViewEntityAction.php(79): Article->view()
#5 /srv/mediawiki/php-1.31.0-wmf.17/extensions/Wikibase/repo/includes/Actions/ViewEntityAction.php(54): Wikibase\ViewEntityAction->showEntityPage()
#6 /srv/mediawiki/php-1.31.0-wmf.17/includes/MediaWiki.php(500): Wikibase\ViewEntityAction->show()
#7 /srv/mediawiki/php-1.31.0-wmf.17/includes/MediaWiki.php(294): MediaWiki->performAction(Article, Title)
#8 /srv/mediawiki/php-1.31.0-wmf.17/includes/MediaWiki.php(858): MediaWiki->performRequest()
#9 /srv/mediawiki/php-1.31.0-wmf.17/includes/MediaWiki.php(524): MediaWiki->main()
#10 /srv/mediawiki/php-1.31.0-wmf.17/index.php(42): MediaWiki->run()
#11 /srv/mediawiki/w/index.php(3): include(string)
#12 {main}I can’t see it myself, presumably because I lack the permissions to see the deleted revision.
Feels like it could be due to MCR, so tentatively CCing @daniel and @Addshore. But without the full stack trace it’s hard to say, so I hope someone from Wikimedia-production-error will pop by soon :)