Asp.net core 2.1 OpenIdConnectOptions with scope doesn't work

Please tell me why I can not add any scope to OpenIdConnectOptions? It doesn't work with an ASP.NET Core MVC client, but with a js client it works fine!

My code...

IdentityServer4 Client registration

public static IEnumerable<Client> GetClients()
{
    return new List<Client>
    {
        new Client
        {
          ClientId = "web",
          ClientName = "Web Client",
          AllowedGrantTypes = GrantTypes.Implicit,
          AllowAccessTokensViaBrowser = true,
          AlwaysIncludeUserClaimsInIdToken = true,
          RedirectUris = {"http://localhost:5002/signin-oidc"},
          PostLogoutRedirectUris = {"http://localhost:5002/signout-callback-oidc"},
          AllowedCorsOrigins = {"http://localhost:5002"},
          AllowedScopes =
            {
              IdentityServerConstants.StandardScopes.OpenId,
              IdentityServerConstants.StandardScopes.Profile,
              "api1"
            },
          AccessTokenLifetime = 300,
          IdentityTokenLifetime = 3600,
          AllowOfflineAccess = true,
        }
    };
}

Next, I add code to the mvc client to use authorization.

Mvc client

JwtSecurityTokenHandler.DefaultInboundClaimTypeMap.Clear();

services.AddAuthorization(options =>
                options.AddPolicy("AdminsOnly", policyUser => 
                       { policyUser.RequireClaim("role", "admin"); }));

services.AddAuthentication(options =>
{
    options.DefaultScheme = "Cookies";
    options.DefaultChallengeScheme = "oidc";
})
.AddCookie("Cookies")
.AddOpenIdConnect("oidc", options =>
{
    options.SignInScheme = "Cookies";

    options.Authority = "http://localhost:5000";
    options.RequireHttpsMetadata = false;
    options.GetClaimsFromUserInfoEndpoint = true;
    options.Scope.Add("api1");

    options.ClientId = "web";
    options.SaveTokens = true;
});

When I try to switch to an action marked with the [authorize] attribute, I get an error

Sorry, there was an error : invalid_scope.

If I delete the line options.Scope.Add("api 1"); then the authentication works. But in this case I can not specify roles and more...

The project can be downloaded here