When editing a section of a translate-enhanced page on Meta:
http://meta.wikimedia.org/w/index.php?title=Wikimedia_Foundation_Board_of_Trustees&action=edit&section=15

I get a fatal exception on preview:
[f2c244f4] 2013-07-08 20:11:09: Fatal exception of type MWException

CC'ing Reedy to get the stacktrace

Not sure that's related, but I'm getting the same error when trying to edit [[m:Tech/News]].

[9d2201c5] 2013-07-10 12:31:12: Fatal exception of type MWException
[6b584201] 2013-07-10 12:32:15: Fatal exception of type MWException
…

Looks like a major bug to me, therefore raising severity.

Same problem when trying to preview [[m:Tech/News/Sandbox]]:

[d7950312] 2013-07-10 13:29:55: Fatal exception of type MWException
[3f22e848] 2013-07-10 13:30:50: Fatal exception of type MWException

2013-07-10 12:31:12 mw1039 metawiki: [9d2201c5] /w/index.php?title=Tech/News&action=submit Exception from line 77 of /usr/local/apache/common-local/php-1.22wmf9/includes/parser/StripState.php: Invalid marker:UNIQ62a4116f994e07ed-languages-00000036-QIN
#0 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/StripState.php(66): StripState->addItem('general', UNIQ62a4116f99...', '<div class="mw-...')
#1 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Parser.php(3992): StripState->addGeneral(UNIQ62a4116f99...', '<div class="mw-...')
#2 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Preprocessor_DOM.php(1152): Parser->extensionSubstitution(Array, Object(PPFrame_DOM))
#3 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Parser.php(3101): PPFrame_DOM->expand(Object(PPNode_DOM), 0)
#4 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Parser.php(1157): Parser->replaceVariables('<languages />?{...')
#5 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Parser.php(386): Parser->internalParse('<languages />?{...')
#6 /usr/local/apache/common-local/php-1.22wmf9/includes/content/WikitextContent.php(300): Parser->parse('<languages />?{...', Object(Title), Object(ParserOptions), true, true, NULL)
#7 /usr/local/apache/common-local/php-1.22wmf9/includes/WikiPage.php(2017): WikitextContent->getParserOutput(Object(Title), NULL, Object(ParserOptions))
#8 /usr/local/apache/common-local/php-1.22wmf9/includes/WikiPage.php(1975): WikiPage->prepareContentForEdit(Object(WikitextContent), NULL, NULL)
#9 [internal function]: WikiPage->prepareTextForEdit('<languages />?{...')
#10 /usr/local/apache/common-local/php-1.22wmf9/includes/Article.php(2021): call_user_func_array(Array, Array)
#11 /usr/local/apache/common-local/php-1.22wmf9/extensions/SpamBlacklist/SpamBlacklist_body.php(50): Article->__call('prepareTextForE...', Array)
#12 /usr/local/apache/common-local/php-1.22wmf9/extensions/SpamBlacklist/SpamBlacklist_body.php(50): Article->prepareTextForEdit('<languages />?{...')
#13 /usr/local/apache/common-local/php-1.22wmf9/extensions/SpamBlacklist/SpamBlacklistHooks.php(26): SpamBlacklist->filter(Object(Title), '<languages />?{...', '', 'simplified a bi...', Object(EditPage))
#14 [internal function]: SpamBlacklistHooks::filterMerged(Object(EditPage), '<languages />?{...', '', 'simplified a bi...')
#15 /usr/local/apache/common-local/php-1.22wmf9/includes/Hooks.php(199): call_user_func_array('SpamBlacklistHo...', Array)
#16 /usr/local/apache/common-local/php-1.22wmf9/includes/GlobalFunctions.php(3834): Hooks::run('EditFilterMerge...', Array)
#17 /usr/local/apache/common-local/php-1.22wmf9/includes/content/ContentHandler.php(1095): wfRunHooks('EditFilterMerge...', Array)
#18 /usr/local/apache/common-local/php-1.22wmf9/includes/EditPage.php(1296): ContentHandler::runLegacyHooks('EditFilterMerge...', Array)
#19 /usr/local/apache/common-local/php-1.22wmf9/includes/EditPage.php(1619): EditPage->runPostMergeFilters(Object(WikitextContent), Object(Status), Object(User))
#20 /usr/local/apache/common-local/php-1.22wmf9/includes/EditPage.php(1194): EditPage->internalAttemptSave(false, false)
#21 /usr/local/apache/common-local/php-1.22wmf9/includes/EditPage.php(416): EditPage->attemptSave()
#22 /usr/local/apache/common-local/php-1.22wmf9/includes/actions/EditAction.php(50): EditPage->edit()
#23 /usr/local/apache/common-local/php-1.22wmf9/includes/actions/EditAction.php(76): EditAction->show()
#24 /usr/local/apache/common-local/php-1.22wmf9/includes/Wiki.php(439): SubmitAction->show()
#25 /usr/local/apache/common-local/php-1.22wmf9/includes/Wiki.php(305): MediaWiki->performAction(Object(Article), Object(Title))
#26 /usr/local/apache/common-local/php-1.22wmf9/includes/Wiki.php(565): MediaWiki->performRequest()
#27 /usr/local/apache/common-local/php-1.22wmf9/includes/Wiki.php(458): MediaWiki->main()
#28 /usr/local/apache/common-local/php-1.22wmf9/index.php(55): MediaWiki->run()
#29 /usr/local/apache/common-local/w/index.php(3): require('/usr/local/apac...')

There's seemingly at least 2 separate bugs here

2013-07-10 13:29:54 mw1210 metawiki: [d7950312] /w/index.php?title=Tech/News/Sandbox&action=submit Exception from line 3993 of /usr/local/apache/common-local/php-1.22wmf9/languages/Language.php: Invalid language code "uk
"
#0 /usr/local/apache/common-local/php-1.22wmf9/extensions/cldr/CldrNames.php(28): Language::getFileName('LocalNames', 'uk?', '.php')
#1 /usr/local/apache/common-local/php-1.22wmf9/extensions/cldr/LanguageNames.body.php(103): CldrNames::getOverrideFileName('uk?')
#2 /usr/local/apache/common-local/php-1.22wmf9/extensions/cldr/LanguageNames.body.php(32): LanguageNames::loadLanguage('uk?')
#3 /usr/local/apache/common-local/php-1.22wmf9/extensions/cldr/LanguageNames.body.php(139): LanguageNames::getNames('uk?', 1, 2)
#4 [internal function]: LanguageNames::coreHook(Array, 'uk?')
#5 /usr/local/apache/common-local/php-1.22wmf9/includes/Hooks.php(199): call_user_func_array('LanguageNames::...', Array)
#6 /usr/local/apache/common-local/php-1.22wmf9/includes/GlobalFunctions.php(3834): Hooks::run('LanguageGetTran...', Array)
#7 /usr/local/apache/common-local/php-1.22wmf9/languages/Language.php(873): wfRunHooks('LanguageGetTran...', Array)
#8 /usr/local/apache/common-local/php-1.22wmf9/languages/Language.php(918): Language::fetchLanguageNames('uk?', 'all')
#9 /usr/local/apache/common-local/php-1.22wmf9/languages/Language.php(399): Language::fetchLanguageName('uk?', 'uk?')
#10 /usr/local/apache/common-local/php-1.22wmf9/extensions/Scribunto/engines/LuaCommon/LanguageLibrary.php(66): Language::isKnownLanguageTag('uk?')
#11 [internal function]: Scribunto_LuaLanguageLibrary->isKnownLanguageTag('uk?')
#12 /usr/local/apache/common-local/php-1.22wmf9/extensions/Scribunto/engines/LuaSandbox/Engine.php(237): call_user_func_array(Array, Array)
#13 [internal function]: Scribunto_LuaSandboxCallback->__call('isKnownLanguage...', Array)
#14 [internal function]: Scribunto_LuaSandboxCallback->isKnownLanguageTag('uk?')
#15 [internal function]: LuaSandboxFunction->call(Object(LuaSandboxFunction))
#16 /usr/local/apache/common-local/php-1.22wmf9/extensions/Scribunto/engines/LuaSandbox/Engine.php(158): call_user_func_array(Array, Array)
#17 /usr/local/apache/common-local/php-1.22wmf9/extensions/Scribunto/engines/LuaCommon/LuaCommon.php(186): Scribunto_LuaSandboxInterpreter->callFunction(Object(LuaSandboxFunction), Object(LuaSandboxFunction))
#18 /usr/local/apache/common-local/php-1.22wmf9/extensions/Scribunto/engines/LuaCommon/LuaCommon.php(643): Scribunto_LuaEngine->executeFunctionChunk(Object(LuaSandboxFunction), Object(PPTemplateFrame_DOM))
#19 /usr/local/apache/common-local/php-1.22wmf9/extensions/Scribunto/common/Hooks.php(108): Scribunto_LuaModule->invoke('assembleNewslet...', Object(PPTemplateFrame_DOM))
#20 [internal function]: ScribuntoHooks::invokeHook(Object(Parser), Object(PPFrame_DOM), Array)
#21 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Parser.php(3560): call_user_func_array('ScribuntoHooks:...', Array)
#22 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Parser.php(3278): Parser->callParserFunction(Object(PPFrame_DOM), '#invoke', Array)
#23 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Preprocessor_DOM.php(1085): Parser->braceSubstitution(Array, Object(PPFrame_DOM))
#24 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Parser.php(3101): PPFrame_DOM->expand(Object(PPNode_DOM), 0)
#25 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Parser.php(1157): Parser->replaceVariables('{{#invoke:Tech ...')
#26 /usr/local/apache/common-local/php-1.22wmf9/includes/parser/Parser.php(386): Parser->internalParse('{{#invoke:Tech ...')
#27 /usr/local/apache/common-local/php-1.22wmf9/includes/content/WikitextContent.php(300): Parser->parse('{{#invoke:Tech ...', Object(Title), Object(ParserOptions), true, true, NULL)
#28 /usr/local/apache/common-local/php-1.22wmf9/includes/EditPage.php(3085): WikitextContent->getParserOutput(Object(Title), NULL, Object(ParserOptions))
#29 /usr/local/apache/common-local/php-1.22wmf9/includes/EditPage.php(2107): EditPage->getPreviewText()
#30 /usr/local/apache/common-local/php-1.22wmf9/includes/EditPage.php(441): EditPage->showEditForm()
#31 /usr/local/apache/common-local/php-1.22wmf9/includes/actions/EditAction.php(50): EditPage->edit()
#32 /usr/local/apache/common-local/php-1.22wmf9/includes/actions/EditAction.php(76): EditAction->show()
#33 /usr/local/apache/common-local/php-1.22wmf9/includes/Wiki.php(439): SubmitAction->show()
#34 /usr/local/apache/common-local/php-1.22wmf9/includes/Wiki.php(305): MediaWiki->performAction(Object(Article), Object(Title))
#35 /usr/local/apache/common-local/php-1.22wmf9/includes/Wiki.php(565): MediaWiki->performRequest()
#36 /usr/local/apache/common-local/php-1.22wmf9/includes/Wiki.php(458): MediaWiki->main()
#37 /usr/local/apache/common-local/php-1.22wmf9/index.php(55): MediaWiki->run()
#38 /usr/local/apache/common-local/w/index.php(3): require('/usr/local/apac...')
#39 {main}

The originally reported error is the same as the first stack trace:

2013-07-08 20:11:09 mw1109 metawiki: [f2c244f4] /w/index.php?title=Wikimedia_Foundation_Board_of_Trustees&action=submit Exception from line 77 of /usr/local/apache/common-local/php-1.22wmf9/includes/parser/StripState.php: Invalid marker:UNIQ8c6cd3f63b6d3cd1-h-0--QIN

(In reply to comment #1)

When editing a section of a translate-enhanced page on Meta:
http://meta.wikimedia.org/w/index.
php?title=Wikimedia_Foundation_Board_of_Trustees&action=edit&section=15

I get a fatal exception on preview:
[f2c244f4] 2013-07-08 20:11:09: Fatal exception of type MWException

This one is probably due to unbalanced <translate> tags in that section. If you edit the whole page, there isn't an error AFAICT.

(In reply to comment #6)

There's seemingly at least 2 separate bugs here

One is bug 44608, the other bug 50606; AFAICS.

As per the stacktrace in comment 6 moving to CLDR; might not be correct but looks like I18N territory.
Might be a dup of bug 50606 as per comment 9 and bug 55803?

I'm just closing this, because other bugs have been failed for these issues.

The backtrace in comment #5 is dupe of bug 44608 which is dupe of bug 56226.
The other backtrace in comment #6 is dupe of bug 50606 as Andre said.