@inject IJSRuntime js

<p><strong style="color:red">Copy and test this in a Blazor Server app.</strong></p>

<TelerikEditor @bind-Value="@PageContentBody" />

<script suppress-error="BL9992">function test() {
        return "success";
    }</script>

@code {
    string PageContentBody { get; set; }

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            // Workaround 1: reorder the code
            //PageContentBody = "<p><strong><span style='color:green;'>Initial Editor value</span></strong></p>";
            //StateHasChanged();

            // Workaround 2: add a delay here
            //await Task.Delay(100);

            var testString = await js.InvokeAsync<string>("test");

            // Workaround 3: add a delay here
            await Task.Delay(100);

            PageContentBody = "<p><strong><span style='color:green;'>Initial Editor value</span></strong></p>";
            StateHasChanged();
        }
    }
}