@Jdforrester-WMF tried to move Talk:Wikibase/Beta_Features/Other_projects_sidebar to Talk:Beta_Features/Other_projects_sidebar (which according to the move log, Greg has already done!), but it failed with the following exception:
2015-08-12 18:01:19 mw1168 mediawikiwiki exception ERROR: [7d0c087d] /w/index.php?title=Special:MovePage&action=submit Flow\Exception\DataModelException from line 247 of /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/Data/Index/FeatureIndex.php: Unable to find specified offset in query results [stacktrace] #0 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/Data/Index/FeatureIndex.php(195): Flow\\Data\\Index\\FeatureIndex->getOffsetFromKey(array, string) #1 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/Data/Index/FeatureIndex.php(492): Flow\\Data\\Index\\FeatureIndex->getOffsetLimit(array, array) #2 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/Data/Index/FeatureIndex.php(440): Flow\\Data\\Index\\FeatureIndex->filterResults(array, array) #3 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/Data/ObjectLocator.php(80): Flow\\Data\\Index\\FeatureIndex->findMulti(array, array) #4 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/Data/ObjectLocator.php(55): Flow\\Data\\ObjectLocator->findMulti(array, array) #5 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/Data/Pager/Pager.php(121): Flow\\Data\\ObjectLocator->find(array, array) #6 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/Block/TopicList.php(481): Flow\\Data\\Pager\\Pager->getPage(Closure$Flow\\Block\\TopicListBlock::getPage;2116714285) #7 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/Block/TopicList.php(268): Flow\\Block\\TopicListBlock->getPage(array) #8 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/View.php(176): Flow\\Block\\TopicListBlock->renderApi(array) #9 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/View.php(69): Flow\\View->buildApiResponse(Flow\\WorkflowLoader, array, string, array) #10 /srv/mediawiki/php-1.26wmf18/extensions/Flow/includes/Content/BoardContent.php(191): Flow\\View->show(Flow\\WorkflowLoader, string) #11 /srv/mediawiki/php-1.26wmf18/includes/page/WikiPage.php(2115): Flow\\Content\\BoardContent->getParserOutput(Title, integer, ParserOptions) #12 /srv/mediawiki/php-1.26wmf18/includes/page/WikiPage.php(2164): WikiPage->prepareContentForEdit(Flow\\Content\\BoardContent, Revision, User) #13 /srv/mediawiki/php-1.26wmf18/includes/MovePage.php(501): WikiPage->doEditUpdates(Revision, User, array) #14 /srv/mediawiki/php-1.26wmf18/includes/MovePage.php(255): MovePage->moveToInternal(User, Title, string, boolean) #15 /srv/mediawiki/php-1.26wmf18/includes/specials/SpecialMovepage.php(583): MovePage->move(User, string, boolean) #16 /srv/mediawiki/php-1.26wmf18/includes/specials/SpecialMovepage.php(123): MovePageForm->doSubmit() #17 /srv/mediawiki/php-1.26wmf18/extensions/Translate/tag/SpecialPageTranslationMovePage.php(135): MovePageForm->execute(NULL) #18 /srv/mediawiki/php-1.26wmf18/includes/specialpage/SpecialPage.php(384): SpecialPageTranslationMovePage->execute(NULL) #19 /srv/mediawiki/php-1.26wmf18/includes/specialpage/SpecialPageFactory.php(553): SpecialPage->run(NULL) #20 /srv/mediawiki/php-1.26wmf18/includes/MediaWiki.php(249): SpecialPageFactory::executePath(Title, RequestContext) #21 /srv/mediawiki/php-1.26wmf18/includes/MediaWiki.php(677): MediaWiki->performRequest() #22 /srv/mediawiki/php-1.26wmf18/includes/MediaWiki.php(474): MediaWiki->main() #23 /srv/mediawiki/php-1.26wmf18/index.php(41): MediaWiki->run() #24 /srv/mediawiki/w/index.php(3): include(string) #25 {main}
Note, this is an occupied page, which might be relevant.