MediaWiki internal error.

Original exception: [ZfkfdCgV-Lf5ugXt29UvnQAAYTA] /wiki/index.php?title=Fakten_und_Zahlen_zur_%C3%9Cberwachung&diff=prev&oldid=18102 Wikimedia\Assert\PostconditionException from line 202 of /www/htdocs/w00ebe77/wiki/vendor/wikimedia/assert/src/Assert.php: Postcondition failed: makeTitleSafe() should always return a Title for the text returned by getRootText().
Backtrace:
#0 /www/htdocs/w00ebe77/wiki/includes/Title.php(1986): Wikimedia\Assert\Assert::postcondition(boolean, string)
#1 /www/htdocs/w00ebe77/wiki/includes/skins/Skin.php(480): Title->getRootTitle()
#2 /www/htdocs/w00ebe77/wiki/includes/OutputPage.php(3121): Skin->getPageClasses(Title)
#3 /www/htdocs/w00ebe77/wiki/includes/skins/SkinTemplate.php(442): OutputPage->headElement(SkinVector)
#4 /www/htdocs/w00ebe77/wiki/includes/skins/SkinTemplate.php(127): SkinTemplate->prepareQuickTemplate()
#5 /www/htdocs/w00ebe77/wiki/includes/skins/SkinTemplate.php(144): SkinTemplate->generateHTML()
#6 /www/htdocs/w00ebe77/wiki/includes/OutputPage.php(2615): SkinTemplate->outputPage()
#7 /www/htdocs/w00ebe77/wiki/includes/MediaWiki.php(947): OutputPage->output(boolean)
#8 /www/htdocs/w00ebe77/wiki/includes/MediaWiki.php(960): MediaWiki->{closure}()
#9 /www/htdocs/w00ebe77/wiki/includes/MediaWiki.php(543): MediaWiki->main()
#10 /www/htdocs/w00ebe77/wiki/index.php(53): MediaWiki->run()
#11 /www/htdocs/w00ebe77/wiki/index.php(46): wfIndexMain()
#12 {main}

Exception caught inside exception handler: [ZfkfdCgV-Lf5ugXt29UvnQAAYTA] /wiki/index.php?title=Fakten_und_Zahlen_zur_%C3%9Cberwachung&diff=prev&oldid=18102 Wikimedia\Assert\PostconditionException from line 202 of /www/htdocs/w00ebe77/wiki/vendor/wikimedia/assert/src/Assert.php: Postcondition failed: makeTitleSafe() should always return a Title for the text returned by getRootText().
Backtrace:
#0 /www/htdocs/w00ebe77/wiki/includes/Title.php(1986): Wikimedia\Assert\Assert::postcondition(boolean, string)
#1 /www/htdocs/w00ebe77/wiki/includes/skins/Skin.php(480): Title->getRootTitle()
#2 /www/htdocs/w00ebe77/wiki/includes/OutputPage.php(3121): Skin->getPageClasses(Title)
#3 /www/htdocs/w00ebe77/wiki/includes/skins/SkinTemplate.php(442): OutputPage->headElement(SkinVector)
#4 /www/htdocs/w00ebe77/wiki/includes/skins/SkinTemplate.php(127): SkinTemplate->prepareQuickTemplate()
#5 /www/htdocs/w00ebe77/wiki/includes/skins/SkinTemplate.php(144): SkinTemplate->generateHTML()
#6 /www/htdocs/w00ebe77/wiki/includes/OutputPage.php(2615): SkinTemplate->outputPage()
#7 /www/htdocs/w00ebe77/wiki/includes/exception/MWExceptionRenderer.php(153): OutputPage->output()
#8 /www/htdocs/w00ebe77/wiki/includes/exception/MWExceptionRenderer.php(65): MWExceptionRenderer::reportHTML(Wikimedia\Assert\PostconditionException)
#9 /www/htdocs/w00ebe77/wiki/includes/exception/MWExceptionHandler.php(106): MWExceptionRenderer::output(Wikimedia\Assert\PostconditionException, integer)
#10 /www/htdocs/w00ebe77/wiki/includes/exception/MWExceptionHandler.php(185): MWExceptionHandler::report(Wikimedia\Assert\PostconditionException)
#11 /www/htdocs/w00ebe77/wiki/includes/MediaWiki.php(576): MWExceptionHandler::handleException(Wikimedia\Assert\PostconditionException, string)
#12 /www/htdocs/w00ebe77/wiki/index.php(53): MediaWiki->run()
#13 /www/htdocs/w00ebe77/wiki/index.php(46): wfIndexMain()
#14 {main}