I have just installed ChartJs.Blazor.Forked (0.2.0) and defined a pie chart. I took the sample from GitHub and adjusted it so I could populate the chart with data from an async service.

The odd part is that the chart will draw and draw correctly. But once it has drawn, then I receive this JSException.

Microsoft.JSInterop.JSException: Could not find a chart with the given id. 247b9e4a-42ce-4ba3-9b1b-ebe8e90ebadc
   at Microsoft.JSInterop.JSRuntime.InvokeAsync[TValue](Int64 targetInstanceId, String identifier, Object[] args)
   at ChartJs.Blazor.Chart.OnAfterRenderAsync(Boolean firstRender)
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)

Blazor code:

                @if (isSetupComplete)
                {
                    <MudCard>
                        <MudCardHeader>
                            <MudText Typo="Typo.h5" Align="Align.Center" Style="color:steelblue"># of Patients by Gender</MudText>
                        </MudCardHeader>
                        <Chart Config="_pieConfig" @ref="_pieChart" Width="300" Height="300"></Chart>
                    </MudCard>
                }
            </MudItem>

C# code is:

        protected async override Task OnInitializedAsync()
        {
            await base.OnInitializedAsync();

            PageNotification.SetProcessing(true);
            try
            {
                #region Populate Data
                ...
                #endregion

                _pieConfig = new PieConfig
                {
                    Options = new PieOptions
                    {
                        Responsive = true,
                        Title = new OptionsTitle
                        {
                            Display = true,
                            Text = "# of Patients by Gender"
                        }
                    }
                };

                PieDataset<int> dataset = new PieDataset<int>(genderValues)
                {
                    BackgroundColor = new[]
                    {
                        ColorUtil.ColorHexString(255, 205, 86), // Slice 2 aka "Yellow"
                        ColorUtil.ColorHexString(54, 162, 235), // Slice 4 aka "Blue"
                    }
                };

                _pieConfig.Data.Datasets.Add(dataset);
                foreach (string gender in genderLabels)
                {
                    _pieConfig.Data.Labels.Add(gender);
                }

                PageNotification.StateChanged();
            }
            catch (Exception ex)
            {
                PageNotification.AddException(ex);
            }
        Done:
            isSetupComplete = true;
            PageNotification.SetProcessing(false);
        }