Anti-Forgery Token was meant for a different claims-based user

Try this:

public ActionResult Logout()
{
    AuthenticationManager.SignOut();
    Session.Abandon();
    return RedirectToAction("Index");
}

That will reload your login page which will provide you a new CSRF token.

You are returning a View, rather than calling RedirectToAction(). So what is happening is the view is running under the context of the logout request, where the user is still logged in. They won't be logged out until the request finishes.

So, try

public ActionResult Logout()
{
    SignInManager.Logout();
    return RedirectToAction("Index", "Home");
}

What worked for me was switching the order of the middlewares used. Add first app.UseAuthentication() and then the antiforgery stuff. This is how I did it:

app.UseAuthentication();
app.Use(next => ctx =>
        {
            var tokens = antiforgery.GetAndStoreTokens(ctx);

            ctx.Response.Cookies.Append("XSRF-TOKEN", tokens.RequestToken,
                new CookieOptions() { HttpOnly = false });

            return next(ctx);
});

Doing it the other way around creates a token that is not meant for authenticated users.