MediaWiki internal error.

Original exception: [Z5f_8C0IuztnSVjQbpUcZQAAAAU] /wiki/Main_Page TypeError: Wikibase\Client\Hooks\LinkedDataSchemaGenerator::createSchemaElement(): Argument #5 ($description) must be of type string, null given, called in /srv/mediawiki/php-master/extensions/Wikibase/client/includes/ClientHooks.php on line 210
Backtrace:
from /srv/mediawiki/php-master/extensions/Wikibase/client/includes/Hooks/LinkedDataSchemaGenerator.php(38)
#0 /srv/mediawiki/php-master/extensions/Wikibase/client/includes/ClientHooks.php(210): Wikibase\Client\Hooks\LinkedDataSchemaGenerator->createSchemaElement(MediaWiki\Title\Title, string, string, Wikibase\DataModel\Entity\ItemId, null)
#1 /srv/mediawiki/php-master/includes/HookContainer/HookContainer.php(155): Wikibase\Client\ClientHooks::onSkinAfterBottomScripts(MediaWiki\Skins\Vector\SkinVector22, string)
#2 /srv/mediawiki/php-master/includes/HookContainer/HookRunner.php(3576): MediaWiki\HookContainer\HookContainer->run(string, array)
#3 /srv/mediawiki/php-master/includes/Output/OutputPage.php(3933): MediaWiki\HookContainer\HookRunner->onSkinAfterBottomScripts(MediaWiki\Skins\Vector\SkinVector22, string)
#4 /srv/mediawiki/php-master/includes/Output/OutputPage.php(5091): MediaWiki\Output\OutputPage->getBottomScripts()
#5 /srv/mediawiki/php-master/includes/skins/Skin.php(703): MediaWiki\Output\OutputPage->tailElement(MediaWiki\Skins\Vector\SkinVector22)
#6 /srv/mediawiki/php-master/includes/Output/OutputPage.php(3194): Skin->outputPageFinal(MediaWiki\Output\OutputPage)
#7 /srv/mediawiki/php-master/includes/actions/ActionEntryPoint.php(162): MediaWiki\Output\OutputPage->output(bool)
#8 /srv/mediawiki/php-master/includes/MediaWikiEntryPoint.php(202): MediaWiki\Actions\ActionEntryPoint->execute()
#9 /srv/mediawiki/php-master/index.php(58): MediaWiki\MediaWikiEntryPoint->run()
#10 /srv/mediawiki/w/index.php(3): require(string)
#11 {main}

Exception caught inside exception handler: [Z5f_8C0IuztnSVjQbpUcZQAAAAU] /wiki/Main_Page TypeError: Wikibase\Client\Hooks\LinkedDataSchemaGenerator::createSchemaElement(): Argument #5 ($description) must be of type string, null given, called in /srv/mediawiki/php-master/extensions/Wikibase/client/includes/ClientHooks.php on line 210
Backtrace:
from /srv/mediawiki/php-master/extensions/Wikibase/client/includes/Hooks/LinkedDataSchemaGenerator.php(38)
#0 /srv/mediawiki/php-master/extensions/Wikibase/client/includes/ClientHooks.php(210): Wikibase\Client\Hooks\LinkedDataSchemaGenerator->createSchemaElement(MediaWiki\Title\Title, string, string, Wikibase\DataModel\Entity\ItemId, null)
#1 /srv/mediawiki/php-master/includes/HookContainer/HookContainer.php(155): Wikibase\Client\ClientHooks::onSkinAfterBottomScripts(MediaWiki\Skins\Vector\SkinVector22, string)
#2 /srv/mediawiki/php-master/includes/HookContainer/HookRunner.php(3576): MediaWiki\HookContainer\HookContainer->run(string, array)
#3 /srv/mediawiki/php-master/includes/Output/OutputPage.php(3933): MediaWiki\HookContainer\HookRunner->onSkinAfterBottomScripts(MediaWiki\Skins\Vector\SkinVector22, string)
#4 /srv/mediawiki/php-master/includes/Output/OutputPage.php(5091): MediaWiki\Output\OutputPage->getBottomScripts()
#5 /srv/mediawiki/php-master/includes/skins/Skin.php(703): MediaWiki\Output\OutputPage->tailElement(MediaWiki\Skins\Vector\SkinVector22)
#6 /srv/mediawiki/php-master/includes/Output/OutputPage.php(3194): Skin->outputPageFinal(MediaWiki\Output\OutputPage)
#7 /srv/mediawiki/php-master/includes/exception/MWExceptionRenderer.php(189): MediaWiki\Output\OutputPage->output()
#8 /srv/mediawiki/php-master/includes/exception/MWExceptionRenderer.php(110): MWExceptionRenderer::reportHTML(TypeError)
#9 /srv/mediawiki/php-master/includes/exception/MWExceptionHandler.php(134): MWExceptionRenderer::output(TypeError, int)
#10 /srv/mediawiki/php-master/includes/exception/MWExceptionHandler.php(238): MWExceptionHandler::report(TypeError)
#11 /srv/mediawiki/php-master/includes/MediaWikiEntryPoint.php(222): MWExceptionHandler::handleException(TypeError, string)
#12 /srv/mediawiki/php-master/includes/actions/ActionEntryPoint.php(81): MediaWiki\MediaWikiEntryPoint->handleTopLevelError(TypeError)
#13 /srv/mediawiki/php-master/includes/MediaWikiEntryPoint.php(208): MediaWiki\Actions\ActionEntryPoint->handleTopLevelError(TypeError)
#14 /srv/mediawiki/php-master/index.php(58): MediaWiki\MediaWikiEntryPoint->run()
#15 /srv/mediawiki/w/index.php(3): require(string)
#16 {main}