Struggling to understand multiple "new lead" activities for same Lead ID
I'm fetching all the "New Lead" (type 12) Activity records in a given interval. In that interval, I notice a fairly good number of Lead IDs which have multiple New Lead Activity records associated. The usual pattern is:
{"id":123,"leadId":8787,"activityDate":"2015-06-01T06:48:58Z","activityTypeId":12,"primaryAttributeValueId":8787,"primaryAttributeValue":"XYZ","attributes":[{"name":"Created Date","value":"2015-05-21"},{"name":"Source Type","value":"Web service API"}]}
{"id":123,"leadId":8787,"activityDate":"2015-06-01T06:54:28Z","activityTypeId":12,"primaryAttributeValueId":4242,"primaryAttributeValue":"Foo Bar","attributes":[{"name":"Created Date","value":"2015-06-01"},{"name":"Source Type","value":"Web service API"}]}
Why would I get multiple entries for the same Lead ID? Any way to avoid that (it basically wastes results I get back from the API, where all I want is to get all Leads created in a specific time interval)? If I can't avoid that, which one of those entries should I "favor"? The first one? The last one?
Thanks!