Spotted in production:
Notice: Undefined index: laplace in /srv/mediawiki/php-1.26wmf17/extensions/CirrusSearch/includes/Hooks.php on line 359
Seems it can easily happen under default settings because $wgCirrusSearchPhraseSuggestProfiles['default'] lacks a 'laplace' entry. Sounds like it should either get one, or the calling code be updated to check for the variable prior to using it.