From prod logstash:
Notice: Array to string conversion in /srv/mediawiki/php-1.25wmf12/includes/utils/IP.php on line 491 Notice: Array to string conversion in /srv/mediawiki/php-1.25wmf12/includes/utils/IP.php on line 503 Warning: preg_match() expects parameter 2 to be string, array given in /srv/mediawiki/php-1.25wmf12/includes/utils/IP.php on line 91 Warning: preg_match() expects parameter 2 to be string, array given in /srv/mediawiki/php-1.25wmf12/includes/utils/IP.php on line 102
IP::parseRange() is being called with an array as the argument instead of a single IP address as expected.