Telerik DataGrid is showing "No records available" with no errors showing

Question

I upgraded my Telerik UI for Blazor to 3.7.0 from 2.3. There were some changes for datagrids, and I change my code accordingly. All of my data grids are showing records except one of them.

The data I am trying to show in Telerik Data Grid is of type T1<T2>.

I have replicated my code in Telerik RELP for blazor which can be accessed here.

<TelerikGrid @ref="@GridRef"
                         Height="30em"
                         TItem="CheckboxPair<SourceModel>"
                         Sortable="true"
                         OnStateInit="@((GridStateEventArgs<CheckboxPair<SourceModel>> args) => OnStateInitHandler(args))"
                         ScrollMode="@GridScrollMode.Scrollable"
                         OnRowRender="@OnRowRenderHandler">
                <GridColumns>
                    
                    <GridColumn Title="Data" Field="@nameof(SourceModel.Title)" Sortable="true">
                        <Template>
                            @{
                                var item = (CheckboxPair<SourceModel>)context;
                                @item.Value.Title
                            }
                        </Template>
                    </GridColumn>
                    <GridColumn Width="15%" Title="@nameof(SourceModel.Type)" Field="@nameof(SourceModel.Type)" Sortable="true">
                        <Template>
                            @{
                                var item = (CheckboxPair<SourceModel>)context;
                                @item.Value.Type
                            }
                        </Template>
                    </GridColumn>
                </GridColumns>
            </TelerikGrid>

@code {
    public class CheckboxPair<T>
    {
        public CheckboxPair(T source, bool isChecked = false)
        {
            Value = source;
            IsChecked = isChecked;
        }
        public bool IsChecked { get; set; }
        public T Value { get; set; }

        public bool IsDisable { get; set; }
    }

    public class SourceModel
    {
        public string Id { get; set; }
        public string Title { get; set; } = string.Empty;
        public string Type { get; set; }
    }

    List<CheckboxPair<SourceModel>> FactorySourceData { get; set; } = new();
    TelerikGrid<CheckboxPair<SourceModel>> GridRef { get; set; }

    protected override void OnInitialized()
    {
        FilterSourceData();
    }

     void OnStateInitHandler(GridStateEventArgs<CheckboxPair<SourceModel>> args)
    {
        args.GridState.SortDescriptors.Add(new SortDescriptor { Member = "Title", SortDirection = ListSortDirection.Ascending });
    }


    void OnRowRenderHandler(GridRowRenderEventArgs args)
    {
        var item = args.Item as CheckboxPair<SourceModel>;

        args.Class = item.IsChecked ? "dim" : args.Class;
    }

    protected void ReadItems(GridReadEventArgs args)
    {
        FilterSourceData();
        args.Data = FactorySourceData;
    }

    void FilterSourceData()
    {
        // This function gets list of data from server and set to FactorySourceData
        
        var data = new SourceModel();
        data.Id = "65hghjg42342";
        data.Title = "data 1";
        data.Type = "Factory";

        var data2 = new SourceModel();
        data2.Id = "hkjhjaksd68";
        data2.Title = "data 2";
        data2.Type = "Factory";

        var checkboxPair1 = new CheckboxPair<SourceModel>(data);
        var checkboxPair2 = new CheckboxPair<SourceModel>(data2, true);

        FactorySourceData = new List<CheckboxPair<SourceModel>> {checkboxPair1, checkboxPair2};
    }

}

After compiling, eventhough there are no errors, the records are not shown. What could be the problem, and what might be the solution?