aspnetcore: Signout doesn't redirect to redirect uri specified in authentication properties.

Describe the bug

While creating a website using OAuth configured as follows:

builder.Services.AddAuthentication(options =>
    {
            options.DefaultAuthenticateScheme = CookieAuthenticationDefaults.AuthenticationScheme;
            options.DefaultSignInScheme = CookieAuthenticationDefaults.AuthenticationScheme;
            options.DefaultChallengeScheme = "GitHub";
    })
    .AddOAuth("GitHub", "GitHub", options =>
    {
        options.SignInScheme = CookieAuthenticationDefaults.AuthenticationScheme;
        options.ClientId = Configuration["ClientId"];
        options.ClientSecret = Configuration["ClientSecret"];
        options.CallbackPath = new PathString(GithubHttpClient.REDIRECT_ENDOPOINT);
        options.AuthorizationEndpoint = "https://github.com/login/oauth/authorize";
        options.TokenEndpoint = "https://github.com/login/oauth/access_token";
        options.UserInformationEndpoint = "https://api.github.com/user";
        options.ClaimsIssuer = "OAuth2-Github";
        options.SaveTokens = true;
        options.Scope.Add("user");
        options.Scope.Add("repo");

        options.ClaimActions.MapJsonKey(ClaimTypes.NameIdentifier, "id");
        options.ClaimActions.MapJsonKey(ClaimTypes.Name, "login");
        options.ClaimActions.MapJsonKey(GithubHttpClient.GITHUB_LOGIN_CLAIM, "login");
        options.ClaimActions.MapJsonKey(GithubHttpClient.GITHUB_NAME_CLAIM, "name");
        options.ClaimActions.MapJsonKey(GithubHttpClient.GITHUB_URL_CLAIM, "html_url");
        options.ClaimActions.MapJsonKey(GithubHttpClient.GITHUB_AVATAR_CLAIM, "avatar_url");

        // Retrieving user information is unique to each provider.
        options.Events = new OAuthEvents
        {
            OnCreatingTicket = async context => { await CreateGitHubAuthTicket(context); }
        };
    })
    .AddCookie();

I have a Signout endpoint defined as follows:

[HttpGet("~/logout")]
[HttpPost("~/logout")]
public IActionResult SignOutCurrentUser()
{
    return SignOut(new AuthenticationProperties { RedirectUri = "/" },
        CookieAuthenticationDefaults.AuthenticationScheme);
}

The logout button is defined as:

<a class="btn btn-lg btn-danger" href="/logout?returnUrl=%2F">Sign out</a>

The site successfully signs out after the signout is made, however after the signout is completed, the site is not redirected to "/" which is the RedirectUri, I specified on the SignOut action.

Further technical details

• ASP.NET Core version: 6.0.0-rc.1.21452.15
• Include the output of dotnet --info:

.NET SDK (reflecting any global.json):
 Version:   6.0.100-rc.1.21463.6
 Commit:    e627d556a1

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.22000
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\6.0.100-rc.1.21463.6\

Host (useful for support):
  Version: 6.0.0-rc.1.21451.13
  Commit:  d7619cd4b1

.NET SDKs installed:
  3.1.410 [C:\Program Files\dotnet\sdk]
  5.0.200-preview.21077.7 [C:\Program Files\dotnet\sdk]
  5.0.301 [C:\Program Files\dotnet\sdk]
  6.0.100-preview.6.21355.2 [C:\Program Files\dotnet\sdk]
  6.0.100-rc.1.21458.32 [C:\Program Files\dotnet\sdk]
  6.0.100-rc.1.21463.6 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0-preview.6.21355.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0-rc.1.21452.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.28 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0-preview.6.21352.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0-preview.7.21360.10 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0-rc.1.21451.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.16 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.0-preview.6.21353.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.0-rc.1.21451.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

• The IDE (VS / VS Code/ VS4Mac) you’re running on, and its version: Microsoft Visual Studio Enterprise 2022 Preview (64-bit) Version 17.0.0 Preview 4.1 [31717.71.d17.0]