Repro steps:

• Create a new Blazor Server app
• Add the following code in index.razor:

@page "/"

<h1>Hello, world!</h1>

Welcome to your new app.

<input value="@message" @oninput="OnInput" />

<p>@message</p>

@code {
    string message;

    void OnInput(ChangeEventArgs e) {
        message = (string)e.Value;
    }
}

• Run it and try mashing on the board when typing in the textbox. Works fine.

• Publish to Azure App Service with the Azure SignalR Service
• Browse to the published app and mash on the keyboard again. Poor typing experience.

• Publish to Azure App Service without the Azure SignalR Service, but with WebSockets enabled. Works fine.

• Switching the code to use @bind works around the issue.

@page "/"

<h1>Hello, world!</h1>

Welcome to your new app.

<input @bind="message" @bind:event="oninput" />

<p>@message</p>

@code {
    string message;

    void OnInput(ChangeEventArgs e) {
        message = (string)e.Value;
    }

}

But in my case I need access to the oninput event callback to run additional logic.