second button click not working before the first one in angularjs

i am having table containing rows and in one column i am having two buttons approve and reject , the problem is reject button works only after the approve button.if i click on reject button it doesn't work on first time. this is my code.

      <tr ng-repeat="item in userRequests">            
                       <td style="border: 1px solid #435363;"></td>
                       <td style="border: 1px solid #435363;"></td>
                       <td ng-if="item.request_status == 0 && item.is_active == null" style="border: 1px solid #435363;">valid till: <input type="text" datepicker ng-model="validate" style="vertical-align: top;" /> <span><button type="button" style = "margin-left: 4px;margin-right: 4px;" class="btn btn-primary btn-xs" ng-click="approveUser(item.email_id,validate)">Approve</button></span>
                       <span><button type="button" class="btn btn-primary btn-xs" ng-click="rejectUser(item.email_id)">Reject</button></span></td>
     </tr>

i am not able to understand which thing is stopping the button to call the function on first click. please see the pic by clicking here the view of table

via Chebli Mohamed