Have you tried enforcing the cookie domain on which you want to set the AMCV Cookie?Ref: cookieDomain 

This would happen in case of Custom Link Calls / TrackAction Calls. In these type calls, the Pagename and Page URL information gets discarded in order to avoid the inflation of Page Views Metric.Hope this helps.

The Paid Search Detection Rules would populate only your Search Engines - Paid Report and help you in your Marketing Channel Processing Rules. The ideal metric to be used against such reports would Searches.