GridView - The AllowFixedGroups property causes a JavaScript error in the GridViewFixedGroupsHelper.SetGroupRowCellsWidth method when a pager is enabled

I was initially going to submit this ticket for a problem I had getting my grid to call my EndCallBack function, but I eventually discovered the problem was actually caused by a JS error within GridViewFixedGroupsHelper.SetGroupRowCellsWidth JS function which occurring before the call to my EndCallBack function (wgEnd).

The error occurs when I set the settings.SettingsBehavior.AllowFixedGroups = true. If I set to false, the error doesn't occur, but I don't get the functionality that I'm looking for. For me, other than the EndCallBack not firing as needed, everything else with the grid behaves normally; paging works, sorting works, etc.

My partial view for the grid has the following (trimmed down for readability):

C#
var grid = Html.DevExpress().GridView<CustomModel>(settings =>  
{  
  settings.Name = "wg";  
  settings.SettingsSearchPanel.Visible = false;  
  settings.CallbackRouteValues = new { Controller = "Home", Action = "wgPartial", w = ViewBag.Id };  
  settings.ClientSideEvents.Init = "wgInit";  
  settings.ClientSideEvents.BeginCallback = "wgBegin";  
  settings.ClientSideEvents.EndCallback = "wgEnd";  
  settings.KeyFieldName = "Id";  
  settings.SettingsLoadingPanel.Mode = GridViewLoadingPanelMode.Default;  
  settings.Settings.ShowFilterRow = false;  
  settings.Settings.VerticalScrollableHeight = 600;  
  settings.Settings.VerticalScrollBarMode = ScrollBarMode.Visible;  
  settings.Settings.UseFixedTableLayout = true;  
  settings.SettingsPager.Mode = GridViewPagerMode.ShowPager;  
  settings.SettingsPager.PageSize = 30;  

  settings.Width = Unit.Percentage(100);  
  settings.Styles.Table.CssClass = "table table-bordered";  
  settings.Styles.Header.CssClass = "header";  

  settings.SettingsBehavior.AllowFixedGroups = true;  
  settings.SettingsBehavior.AllowSelectByRowClick = false;  
  settings.SettingsBehavior.AutoExpandAllGroups = true;  
  settings.SettingsBehavior.AllowGroup = false;  
  settings.SettingsBehavior.AllowDragDrop = false;  
  settings.SettingsBehavior.AllowSelectByRowClick = false;  
  settings.SettingsBehavior.AllowSelectSingleRowOnly = false;  

  settings.SettingsDetail.ShowDetailRow = true;  
  settings.SettingsDetail.ShowDetailButtons = false;  
  settings.SettingsDetail.AllowOnlyOneMasterRowExpanded = false;  

  settings.Columns.Add(m =>  
  {  
    m.FieldName = "Prop1";  
    m.GroupIndex = 0;  
    m.Caption = "Prop #1";  
    m.SetGroupRowTemplateContent(diTemplate =>  
    {  
      string name = ((string)DataBinder.Eval(diTemplate.DataItem, nameof(CustomModel.Prop1)));  
      ViewContext.Writer.Write(string.IsNullOrEmpty(name) ? "<i>(No 1 Specified)</i>" : name);  
    });  
  });  

  settings.Columns.Add(m =>  
  {  
    m.FieldName = "Prop2";  
    m.GroupIndex = 1;  
    m.Caption = "Prop #2";  
    m.SetGroupRowTemplateContent(diTemplate =>  
    {  
      string name = ((string)DataBinder.Eval(diTemplate.DataItem, nameof(CustomModel.Prop2)));  
      ViewContext.Writer.Write(string.IsNullOrEmpty(name) ? "<i>(No 2 Specified)</i>" : name);  
    });  
  });  

  settings.Columns.Add(m =>  
  {  
    m.FieldName = "Prop3";  
    m.Caption = "Prop #3";  
  });  

  settings.Columns.Add(m =>  
  {  
    m.FieldName = "Prop4";  
    m.Caption = "Prop #4";  
  });  
});  
@grid.Bind(Model).GetHtml()  

With that I get a "Uncaught TypeError: Cannot read property 'style' of undefined" JS error within GridViewFixedGroupsHelper.SetGroupRowCellsWidth:

JavaScript
groupRow.cells[level + 1].style.width = totalWidth - ASPx.GetLeftRightBordersAndPaddingsSummaryValue(groupRow.cells[level + 1]) + "px";  

"groupRow.cells" is an HTMLCollection with one element and "level" == 0". groupRow.cells[0] is the grouped header with "(No 1 Specified)" in it. "level + 1" is undefined, naturally, as the collection only has one element. Once that error is hit, my EndCallBack method never gets called again… unless oddly enough I'm switching from a page > 1 back to page == 1.