I know it is not a site wide issue and is probably a minor thing, but have you also looked into tracking done by embedded media, like embedded Youtube videos?

I know it is not a site wide issue and is probably a minor thing, but have you also looked into tracking done by embedded media, like embedded Youtube videos? In case of Youtube there is a no-cookie domain that can be used for embedding and then, while client still sends the request to them, no additional cookie is set.