I was checking to make sure that the visitor count was the same from Piwik 2.8 to 2.10. I notice that the visotor count is now off and showing different numbers. When I tried to troubleshoot the issue, I found the following line.
Referrers[2015-02-04 17:14:50] [3eb41] Existing visit detected, but creating new visit because campaign information is different than last action.
When did the Referrer plug in start to create a new visit when the campaign data changes? Is this how Google does it?