Piwik tracking more events than GoogleAnalytics

I have a event that is fired in Piwik and Google Analytics when the pages loads firing something like “The product was viewed”. However, the numbers are not matching for in general 9% of difference.

PS1: I have the average of 100k events by day.
PS2: The server are configured ok:

  • Load balance
  • Redis
  • All optimisations.
    PS3: I am firing the Google without noninteraction flag. Can it be a problem?

Thanks for the attention and btw thanks for piwik.