[Blazor p8] OnInitializedAsync is executed for twice on pre-render

[ctrl-alt-d]

Issue

OnInitializedAsync is executed for twice when page has been served as "pre-render".

Version

[dani@localhost tw]$ dotnet --version
3.0.100-preview8-013656

Steps to reproduce and screen shots:

@page "/"
@inject IUriHelper UriHelper

<h1>Hello, world!</h1>

Welcome to your new app.

@code{

    protected async override Task OnInitializedAsync()
    {
        System.Console.WriteLine("_*   ");
        System.Console.WriteLine("_**************************");
        System.Console.WriteLine("_***** Pre render ******");
        System.Console.WriteLine("_**************************");
        System.Console.WriteLine("_   ");
        return;
    }
}

And I see is executed for twice only on pre-render:

Has it some explanation?

The question on stackoverfow: Blazor UriHelper.NavigateTo is calling the page twice

[ctrl-alt-d]

Related: #13172

[mkArtakMSFT]

Thanks for contacting us, @ctrl-alt-d.
The behavior you're seeing is by-design. We you see the OnInitializedAsync called once during pre-rendering and once during the rendering.

[gitskab]

Hi,

I'm having the same issue but only as I publish my app to Azure App Services. If I switch RenderMode to Server then it gets called only once but then contextAccessor.HttpContext is null when injected into my service class.

On my localhost it works fine in both cases..

Am I doing something wrong here?