Page Not Found - URL Undefined


I am running Wordpress 4.2.4.

I am getting alot of report of “Page Not Found” for perfectly valid URL and then followed by 2 to 11 times of " /undefined" added to the end of the valid page URL such as: (2X to 11X)

Each time the “/undefined” happen I get a Page Not Found?

I have tried browsing my website anonymously as a user - but I am not able to see such a problem happening.

Does anyone have this problem?

Is Piwik malfunctioning in some way?