reported in https://forum.matomo.org/t/warning-messages-ucwords-expects-exactly-1-parameter-after-update-to-3-11-0/33611
introduced in #14449

It seems like the second parameter has only been introduced in PHP 5.5.16, but Matomo supports (I think 5.5.9+)
https://3v4l.org/Uf3Ya
https://stackoverflow.com/questions/42575390/is-ucwords-delimiter-parameter-supported-in-php-5-6