As mentioned in http://dev.piwik.org/trac/ticket/4230#comment:3, an optional match was added to the log detection regex
The regex changes are incorrect. The changes will match "18.104.22.168, 22.214.171.124" as one group. The desired behavior is "126.96.36.199" to be matched and the rest ignored. Note: the brackets you used ('[ ... ]') will create a character class and because you place a space plus \S (represents any non-space character) within it, the change will match any character.