MediaWiki internal error.

Original exception: [YLeAedhRdWDpI1EV4G2NnQAAAC0] [no req] TypeError from line 1007 of /includes/parser/Parser.php: Return value of Parser::getTitle() must be an instance of Title, null returned
Backtrace:
#0 /extensions/PageForms/includes/PF_FormUtils.php(498): Parser->getTitle()
#1 /extensions/PageForms/includes/PF_FormPrinter.php(911): PFFormUtils::getFormDefinition(Parser, string, integer)
#2 /extensions/PageForms/specials/PF_RunQuery.php(88): PFFormPrinter->formHTML(string, boolean, boolean, integer, NULL, NULL, NULL, boolean, boolean)
#3 /extensions/PageForms/specials/PF_RunQuery.php(28): PFRunQuery->printPage(string, boolean)
#4 /includes/specialpage/SpecialPage.php(600): PFRunQuery->execute(string)
#5 /includes/specialpage/SpecialPageFactory.php(635): SpecialPage->run(string)
#6 /includes/specialpage/SpecialPageFactory.php(693): MediaWiki\SpecialPage\SpecialPageFactory->executePath(Title, RequestContext, boolean, MediaWiki\Linker\LinkRenderer)
#7 /includes/parser/Parser.php(3144): MediaWiki\SpecialPage\SpecialPageFactory->capturePath(Title, RequestContext, MediaWiki\Linker\LinkRenderer)
#8 /includes/parser/PPFrame_Hash.php(253): Parser->braceSubstitution(array, PPFrame_Hash)
#9 /includes/parser/Parser.php(2887): PPFrame_Hash->expand(PPNode_Hash_Tree, integer)
#10 /includes/parser/Parser.php(1556): Parser->replaceVariables(string)
#11 /includes/parser/Parser.php(651): Parser->internalParse(string)
#12 /includes/content/WikitextContent.php(374): Parser->parse(string, Title, ParserOptions, boolean, boolean, NULL)
#13 /includes/content/AbstractContent.php(590): WikitextContent->fillParserOutput(Title, NULL, ParserOptions, boolean, ParserOutput)
#14 /includes/Revision/RenderedRevision.php(263): AbstractContent->getParserOutput(Title, NULL, ParserOptions, boolean)
#15 /includes/Revision/RenderedRevision.php(235): MediaWiki\Revision\RenderedRevision->getSlotParserOutputUncached(WikitextContent, boolean)
#16 /includes/Revision/RevisionRenderer.php(215): MediaWiki\Revision\RenderedRevision->getSlotParserOutput(string)
#17 /includes/Revision/RevisionRenderer.php(152): MediaWiki\Revision\RevisionRenderer->combineSlotOutput(MediaWiki\Revision\RenderedRevision, array)
#18 [internal function]: MediaWiki\Revision\RevisionRenderer->MediaWiki\Revision\{closure}(MediaWiki\Revision\RenderedRevision, array)
#19 /includes/Revision/RenderedRevision.php(197): call_user_func(Closure, MediaWiki\Revision\RenderedRevision, array)
#20 /includes/Storage/DerivedPageDataUpdater.php(1315): MediaWiki\Revision\RenderedRevision->getRevisionParserOutput()
#21 /includes/Storage/PageUpdater.php(752): MediaWiki\Storage\DerivedPageDataUpdater->getCanonicalParserOutput()
#22 /includes/page/WikiPage.php(2015): MediaWiki\Storage\PageUpdater->saveRevision(CommentStoreComment, integer)
#23 /includes/EditPage.php(2456): WikiPage->doEditContent(WikitextContent, CommentStoreComment, integer, boolean, User, string, array, integer)
#24 /includes/EditPage.php(1723): EditPage->internalAttemptSave(array, boolean)
#25 /includes/EditPage.php(680): EditPage->attemptSave(array)
#26 /includes/actions/EditAction.php(71): EditPage->edit()
#27 /includes/actions/SubmitAction.php(38): EditAction->show()
#28 /includes/MediaWiki.php(527): SubmitAction->show()
#29 /includes/MediaWiki.php(313): MediaWiki->performAction(Article, Title)
#30 /includes/MediaWiki.php(940): MediaWiki->performRequest()
#31 /includes/MediaWiki.php(543): MediaWiki->main()
#32 /index.php(53): MediaWiki->run()
#33 /index.php(46): wfIndexMain()
#34 {main}