[{reqId}] {exception_url}   PHP Notice: Undefined index: questions

from /srv/mediawiki/php-1.37.0-wmf.7/extensions/GrowthExperiments/includes/WelcomeSurvey.php(137)
#0 /srv/mediawiki/php-1.37.0-wmf.7/extensions/GrowthExperiments/includes/WelcomeSurvey.php(137): MWExceptionHandler::handleError(integer, string, string, integer, array)
#1 /srv/mediawiki/php-1.37.0-wmf.7/extensions/GrowthExperiments/includes/WelcomeSurvey.php(347): GrowthExperiments\WelcomeSurvey->getQuestions(string)
#2 /srv/mediawiki/php-1.37.0-wmf.7/extensions/GrowthExperiments/includes/WelcomeSurveyHooks.php(80): GrowthExperiments\WelcomeSurvey->getRedirectUrl(string)
#3 /srv/mediawiki/php-1.37.0-wmf.7/includes/HookContainer/HookContainer.php(160): GrowthExperiments\WelcomeSurveyHooks->onBeforeWelcomeCreation(string, string)
#4 /srv/mediawiki/php-1.37.0-wmf.7/includes/HookContainer/HookRunner.php(1032): MediaWiki\HookContainer\HookContainer->run(string, array)
#5 /srv/mediawiki/php-1.37.0-wmf.7/includes/specials/SpecialCreateAccount.php(157): MediaWiki\HookContainer\HookRunner->onBeforeWelcomeCreation(string, string)
#6 /srv/mediawiki/php-1.37.0-wmf.7/includes/specialpage/LoginSignupSpecialPage.php(357): SpecialCreateAccount->successfulAction(boolean)
#7 /srv/mediawiki/php-1.37.0-wmf.7/includes/specialpage/SpecialPage.php(646): LoginSignupSpecialPage->execute(NULL)
#8 /srv/mediawiki/php-1.37.0-wmf.7/includes/specialpage/SpecialPageFactory.php(1390): SpecialPage->run(NULL)
#9 /srv/mediawiki/php-1.37.0-wmf.7/includes/MediaWiki.php(314): MediaWiki\SpecialPage\SpecialPageFactory->executePath(string, RequestContext)
#10 /srv/mediawiki/php-1.37.0-wmf.7/includes/MediaWiki.php(917): MediaWiki->performRequest()
#11 /srv/mediawiki/php-1.37.0-wmf.7/includes/MediaWiki.php(551): MediaWiki->main()
#12 /srv/mediawiki/php-1.37.0-wmf.7/index.php(53): MediaWiki->run()
#13 /srv/mediawiki/php-1.37.0-wmf.7/index.php(46): wfIndexMain()
#14 /srv/mediawiki/w/index.php(3): require(string)
#15 {main}