Mudblazor datagrid rows not selecting with RowClassFunc

I am working with server side paging and filtering for a mudblazor datagrid, and upon checking a row, everything saves properly, but I cannot get the rows to recheck on page change, with the RowClassFunc.

I tried creating a RowClassFunc applying the class "selected" according to others who have had success, but it is not working.

<MudDataGrid             T="ObservationListModel"             MultiSelection="@true"             @ref="_dataGrid"             @bind-SelectedItems="selectedItems"             ServerData="LoadGridData"             SortMode="SortMode.Multiple"             Filterable="true"            RowClassFunc="SelectedRowClassFunc"            Hideable="false"             Elevation="5"             Dense="@true"><ToolBarContent><MudSpacer /><MudTextField T="string" Value="@_requestDto.Search" Placeholder="Search" Adornment="Adornment.Start" Immediate="false"                              AdornmentIcon="@Icons.Material.Filled.Search" IconSize="Size.Medium" Class="mt-0" ValueChanged="OnSearchChange"></MudTextField></ToolBarContent><Columns><SelectColumn T="ObservationListModel" /><TemplateColumn Sortable="@false" Filterable="@false" Title="Detail" ><CellTemplate><MudStack Row><MudButton Size="@Size.Small" Variant="@Variant.Filled" Href="@($"obsdetail/{context.Item.ReferenceID}/{context.Item.OriginalDataID}")" Color="@Color.Primary">View</MudButton></MudStack></CellTemplate></TemplateColumn><PropertyColumn Property="x => x.ScientificName" Title="Scientific Name" Sortable="true" /><PropertyColumn Property="x => x.ObservationDate" Title="Observation Date" Sortable="true" Filterable="false" /><PropertyColumn Property="x => x.Class" Title="Class" Sortable="true"/><PropertyColumn Property="x => x.CountyName" Title="County" Sortable="true" /><PropertyColumn Property="x => x.Observer" Title="Observer" Sortable="true" /><PropertyColumn Property="x => x.ReviewStatus" Title="Review Status" Sortable="true" /></Columns><PagerContent><MudText>@($"{selectedItems.Count} items selected")</MudText><MudDataGridPager T="ObservationListModel"/></PagerContent></MudDataGrid>

@code {    private MudDataGrid<ObservationListModel>? _dataGrid;    private ObsRequestModel _requestDto = new();    private HashSet<ObservationListModel> selectedItems { get; set; } = new HashSet<ObservationListModel>();    private async Task Search()    {        if (_dataGrid is not null)        {            await _dataGrid!.ReloadServerData();        }    }    private async Task OnSearchChange(string newValue)    {        _requestDto.Search = newValue;        await Search();    }    private async Task<GridData<ObservationListModel>> LoadGridData(GridState<ObservationListModel> state)    {        _requestDto.Filters.Clear();        _requestDto.Page = state.Page + 1;        _requestDto.PageSize = state.PageSize;        // Extract sorting information        var sorting = state.SortDefinitions.FirstOrDefault(); // Assuming single column sorting        if (sorting != null)        {            _requestDto.SortColumn = sorting.SortBy;            _requestDto.SortDirection = sorting.Descending == false ? "asc" : "desc"; // Convert Enum to string or appropriate format        }        // Extract filtering information        foreach (var filter in state.FilterDefinitions)        {            if (filter.Value != null) {                var colString = filter.Title.ToString();                var valString = colString == "County" ? await ReferenceService.GetCountyFips(filter.Value.ToString()) : filter.Value.ToString();                _requestDto.Filters.Add(new FilterDefinition                {                    Column = colString,                    Operator = filter.Operator.ToString(),                    Value = valString                });            }             else if (filter.Operator.ToLower() == "is empty" || filter.Operator.ToLower() == "is not empty")            {                _requestDto.Filters.Add(new FilterDefinition                {                    Column = filter.Title.ToString(),                    Operator = filter.Operator.ToString(),                    Value = "0", // Assuming the value is a string, adjust as necessary                });            }         }        ObListDTO Response = await ReferenceService.GetAllObs(_requestDto);        GridData<ObservationListModel> data = new()        {            Items = Response.Items,            TotalItems = Response.ItemTotalCount        };        return data;    }    private async Task OnStartDateChanged(DateTime? newDate)    {        _requestDto.StartDate = newDate;        await DateChange();    }    private async Task OnEndDateChanged(DateTime? newDate)    {        _requestDto.EndDate = newDate;        await DateChange();    }    private async Task DateChange()    {        if (_dataGrid is not null)        {            await _dataGrid!.ReloadServerData();        }    }    public void Dispose()    {    }    private string SelectedRowClassFunc(ObservationListModel element, int rowNumber)    {        return selectedItems.Contains(element) ? "selected" : string.Empty;    }