jQuery Grid Plugin - jqGrid

I recently updated a project from JQGrid 4.2.0 to 4.6.0 and sort is not working. I also implemented bootstrap 3.0 and didn't make any code changes other than some minor styling so I would assume it should work but it is not. Everything else appears to be working fine except sorting.  I did some research online and the common solution appears to be to set loadonce to true and I've tried this and sorting works fine.  However, I cannot set loadonce to true since our data sets can exceed 50,000 so multilple loads will be required.  Some code snippets is listed below.  Thanks in advance.

var colNames = ['', '', '..', 'Name', 'Age', '...', '...', '...'];

      colNames.push('Final Time', '', '', '');

      var colModel = [
...
        { name: 'Name', index: 'Name', editable: true },
        { name: 'Age', index: 'Age', width: 30, align: 'center', editable: true },
....
      ];
//      for(var j = 0; j < legIds.length; j++) {
//        colModel.push({ name: 'Leg' + (j + 1), index: 'Leg' + (j + 1), editable: true, width: 70, align: 'right' });
//      }
…
      
      grid = $("#grid");
      grid.jqGrid({
          url: '/Results/GetData?&courseid=' + courseID,
          prmNames: {
            rows: 'pageSize',
            sort: 'sortOrder',
            order: 'sortDir',
            nd: null
          },
          datatype: 'json',
          jsonReader : {
            id : 'ID',
            root: 'entries',
            repeatitems: false
          },
          colNames: colNames,
          colModel: colModel,
          height: 'auto',
          autowidth: true,
          altRows: false,
          caption: '',
          cellEdit: false,
          cellsubmit: 'clientArray',
          grouping: true,
          toolbar: [false, 'top'],
          pager: '#pager',
          toppager: false,
          rowNum: 25,
          // rowTotal: 50,
          rowList: [25, 50, 100, 250],
          viewrecords: true,
          onSelectRow: onGridSelectRow,
          ondblClickRow: onGridDblClickRow,
          onPaging: onGridPaging,
          loadComplete: onGridLoadComplete
        });