GravityForms Version 1.6.10
in form_display.php in function process_form line 13 $lead variable is assigned
$lead = array();
later in process_form function on line 80 $lead varible is passed to handle_submission function
$confirmation = self::handle_submission($form, $lead, $ajax);
at this point $lead variable is still an empty array. Then in handle_submission function on line 886 $lead is passed to RGFormsModel::save_lead $lead is still empty array()
RGFormsModel::save_lead($form, $lead);
Then in forms_model.php in function RGFormsModel::save_lead on line 807 there is
if($lead == null){
$lead is still an empty array which is not the same as null so the code that actually inserts the lead into the db never gets called.