Blazor Custom AuthenticationStateProvider not working

I've implemented this class in my Blazor server project (using .net 6.0).

public class CustomAuthenticationStateProvider : AuthenticationStateProvider{    public CustomAuthenticationStateProvider(ProtectedSessionStorage sessionStorage)    {        _sessionStorage = sessionStorage;    }    // also contains working code which isn't relevant to this problem (so not shown for brevity).}

The DI startup code looks like this:

builder.Services.AddAuthenticationCore();builder.Services.AddRazorPages();builder.Services.AddScoped<ProtectedSessionStorage>();builder.Services.AddScoped<AuthenticationStateProvider, CustomAuthenticationStateProvider>();

However, when trying to access this from the login page (a razor component), the CustomAuthenticationStateProvider is not found.

Markup (relevant lines only):

@inject AuthenticationStateProvider authStateProvider<div class="button login" @onclick="() => DoLogin()">   Login</div>

The method which errors in the markup:

private async Task DoLogin(){    var customAuthStateProvider = authStateProvider as CustomAuthenticationStateProvider;    await customAuthStateProvider.UpdateAuthenticationState(new UserSession    {        UserName = _inputUsername,        Role = "admin"    });}

However, customAuthStateProvider is always null because authStateProvider (which is injected into the razor component) is not the scoped instance of CustomAuthenticationStateProvider ... it's just some other instance of AuthenticationStateProvider.