A page containing the wikitext <ref><gallery>a</gallery></ref> results in the following:

[cb063d04] /w/index.php?title=Sandbox&action=submit Exception from line 77 of /srv/mediawiki/php-master/includes/parser/StripState.php: Invalid marker: UNIQdaa27898b491f957-gallery-00000006-QINU

Backtrace:

#0 /srv/mediawiki/php-master/includes/parser/StripState.php(66): StripState->addItem(string, string, string)
#1 /srv/mediawiki/php-master/includes/parser/Parser.php(4199): StripState->addGeneral(string, string)
#2 /srv/mediawiki/php-master/includes/parser/Preprocessor_Hash.php(1173): Parser->extensionSubstitution(array, PPFrame_Hash)
#3 /srv/mediawiki/php-master/includes/parser/Parser.php(3281): PPFrame_Hash->expand(PPNode_Hash_Tree, integer)
#4 /srv/mediawiki/php-master/includes/parser/Parser.php(1239): Parser->replaceVariables(string)
#5 /srv/mediawiki/php-master/includes/parser/Parser.php(612): Parser->internalParse(string, boolean, boolean)
#6 /srv/mediawiki/php-master/extensions/Cite/Cite_body.php(670): Parser->recursiveTagParse(string)
#7 /srv/mediawiki/php-master/extensions/Cite/Cite_body.php(1071): Cite->referencesFormat(string)
#8 /srv/mediawiki/php-master/includes/Hooks.php(206): Cite->checkRefsNoReferences(boolean, Parser, string)
#9 /srv/mediawiki/php-master/includes/GlobalFunctions.php(3984): Hooks::run(string, array, NULL)
#10 /srv/mediawiki/php-master/includes/parser/Parser.php(406): wfRunHooks(string, array)
#11 /srv/mediawiki/php-master/includes/StubObject.php(105): Parser->parse(string, Title, ParserOptions, boolean, boolean, NULL)
#12 /srv/mediawiki/php-master/includes/StubObject.php(125): StubObject->_call(string, array)
#13 /srv/mediawiki/php-master/includes/content/WikitextContent.php(338): StubObject->__call(string, array)
#14 /srv/mediawiki/php-master/includes/content/AbstractContent.php(490): WikitextContent->fillParserOutput(Title, NULL, ParserOptions, boolean, ParserOutput)
#15 /srv/mediawiki/php-master/extensions/SpamBlacklist/SpamBlacklistHooks.php(29): AbstractContent->getParserOutput(Title, NULL, ParserOptions, boolean)
#16 /srv/mediawiki/php-master/includes/Hooks.php(206): SpamBlacklistHooks::filterMergedContent(RequestContext, WikitextContent, Status, string, User, boolean)
#17 /srv/mediawiki/php-master/includes/GlobalFunctions.php(3984): Hooks::run(string, array, NULL)
#18 /srv/mediawiki/php-master/includes/EditPage.php(1425): wfRunHooks(string, array)
#19 /srv/mediawiki/php-master/includes/EditPage.php(1816): EditPage->runPostMergeFilters(WikitextContent, Status, User)
#20 /srv/mediawiki/php-master/includes/EditPage.php(1286): EditPage->internalAttemptSave(boolean, boolean)
#21 /srv/mediawiki/php-master/includes/EditPage.php(522): EditPage->attemptSave()
#22 /srv/mediawiki/php-master/includes/actions/EditAction.php(56): EditPage->edit()
#23 /srv/mediawiki/php-master/includes/actions/SubmitAction.php(40): EditAction->show()
#24 /srv/mediawiki/php-master/includes/MediaWiki.php(414): SubmitAction->show()
#25 /srv/mediawiki/php-master/includes/MediaWiki.php(282): MediaWiki->performAction(Article, Title)
#26 /srv/mediawiki/php-master/includes/MediaWiki.php(584): MediaWiki->performRequest()
#27 /srv/mediawiki/php-master/includes/MediaWiki.php(435): MediaWiki->main()
#28 /srv/mediawiki/php-master/index.php(46): MediaWiki->run()
#29 /srv/mediawiki/w/index.php(3): include(string)
#30 {main}

I can reproduce this both on production and beta labs, but not locally.

Version: unspecified
Severity: normal