This error started after pushing 1.32.0-wmf.18 to wikipedia wikis.
Exception was visible for urls like: https://en.wikipedia.org/wiki/Zimbabwe?action=render
prepareForParse() nor setReviewedVersions() called yet
/srv/mediawiki/php-1.32.0-wmf.18/extensions/FlaggedRevs/backend/FRInclusionManager.php:133
#0 /srv/mediawiki/php-1.32.0-wmf.18/extensions/FlaggedRevs/backend/FlaggedRevs.class.php(622): FRInclusionManager->getReviewedTemplateVersion(Title) #1 /srv/mediawiki/php-1.32.0-wmf.18/includes/parser/Parser.php(3575): Closure$FlaggedRevs::parseStableRevision(Title, Parser) #2 /srv/mediawiki/php-1.32.0-wmf.18/includes/parser/Parser.php(3667): Parser->fetchCurrentRevisionOfTitle(Title) #3 /srv/mediawiki/php-1.32.0-wmf.18/includes/parser/Parser.php(3603): Parser::statelessFetchTemplate(Title, Parser) #4 /srv/mediawiki/php-1.32.0-wmf.18/includes/parser/Parser.php(3537): Parser->fetchTemplateAndTitle(Title) #5 /srv/mediawiki/php-1.32.0-wmf.18/includes/parser/Parser.php(3297): Parser->getTemplateDom(Title) #6 /srv/mediawiki/php-1.32.0-wmf.18/includes/parser/Preprocessor_Hash.php(1114): Parser->braceSubstitution(array, PPFrame_Hash) #7 /srv/mediawiki/php-1.32.0-wmf.18/includes/parser/Parser.php(2999): PPFrame_Hash->expand(PPNode_Hash_Tree, integer) #8 /srv/mediawiki/php-1.32.0-wmf.18/includes/parser/Parser.php(1345): Parser->replaceVariables(string) #9 /srv/mediawiki/php-1.32.0-wmf.18/includes/parser/Parser.php(474): Parser->internalParse(string) #10 /srv/mediawiki/php-1.32.0-wmf.18/includes/content/WikitextContent.php(341): Parser->parse(string, Title, ParserOptions, boolean, boolean, integer) #11 /srv/mediawiki/php-1.32.0-wmf.18/includes/content/AbstractContent.php(516): WikitextContent->fillParserOutput(Title, integer, ParserOptions, boolean, ParserOutput) #12 /srv/mediawiki/php-1.32.0-wmf.18/extensions/FlaggedRevs/backend/FlaggedRevs.class.php(644): AbstractContent->getParserOutput(Title, integer, ParserOptions) #13 /srv/mediawiki/php-1.32.0-wmf.18/extensions/FlaggedRevs/backend/FlaggedRevs.class.php(566): FlaggedRevs::parseStableRevision(FlaggedRevision, ParserOptions) #14 /srv/mediawiki/php-1.32.0-wmf.18/includes/poolcounter/PoolCounterWorkViaCallback.php(69): Closure$FlaggedRevs::parseStableRevisionPooled() #15 /srv/mediawiki/php-1.32.0-wmf.18/includes/poolcounter/PoolCounterWork.php(123): PoolCounterWorkViaCallback->doWork() #16 /srv/mediawiki/php-1.32.0-wmf.18/extensions/FlaggedRevs/backend/FlaggedRevs.class.php(582): PoolCounterWork->execute() #17 /srv/mediawiki/php-1.32.0-wmf.18/extensions/FlaggedRevs/frontend/FlaggablePageView.php(749): FlaggedRevs::parseStableRevisionPooled(FlaggedRevision, ParserOptions) #18 /srv/mediawiki/php-1.32.0-wmf.18/extensions/FlaggedRevs/frontend/FlaggablePageView.php(391): FlaggablePageView->showStableVersion(FlaggedRevision, string, string) #19 /srv/mediawiki/php-1.32.0-wmf.18/extensions/FlaggedRevs/frontend/FlaggedRevsUI.hooks.php(204): FlaggablePageView->setPageContent(boolean, boolean) #20 /srv/mediawiki/php-1.32.0-wmf.18/includes/Hooks.php(174): FlaggedRevsUIHooks::onArticleViewHeader(Article, boolean, boolean) #21 /srv/mediawiki/php-1.32.0-wmf.18/includes/Hooks.php(202): Hooks::callHook(string, array, array, NULL) #22 /srv/mediawiki/php-1.32.0-wmf.18/includes/page/Article.php(524): Hooks::run(string, array) #23 /srv/mediawiki/php-1.32.0-wmf.18/includes/actions/ViewAction.php(68): Article->view() #24 /srv/mediawiki/php-1.32.0-wmf.18/includes/MediaWiki.php(501): ViewAction->show() #25 /srv/mediawiki/php-1.32.0-wmf.18/includes/MediaWiki.php(294): MediaWiki->performAction(Article, Title) #26 /srv/mediawiki/php-1.32.0-wmf.18/includes/MediaWiki.php(868): MediaWiki->performRequest() #27 /srv/mediawiki/php-1.32.0-wmf.18/includes/MediaWiki.php(525): MediaWiki->main() #28 /srv/mediawiki/php-1.32.0-wmf.18/index.php(42): MediaWiki->run() #29 /srv/mediawiki/w/index.php(3): include(string) #30 {main}