Identity server 4. Identity resource claims in resource owner password flow - identityserver4

Question

I'm using resource owner password grand type. I implemented 2 interfaces: IResourceOwnerPasswordValidator and IProfileService. When I request a token, I get to the ResourceOwnerPasswordValidator, after successful validation I expect ProfileService provides me with requested climes. But it never does.
The thing is the RequestedClaimTypes from ProfileDataRequestContext in the ProfileService is always empty, as a result I can't filter out claims which weren't asked.
I expect it contains all claims, which are related to the requested scopes.
For example if I request such scopes as email or "profile" then I expect claims like "email", "first_name", "preferred_username" and others to be in the RequestedClaimTypes list.
There is simple clients and identity resource config:
return new List<IdentityResource>
{
new IdentityResources.OpenId(),
new IdentityResources.Profile(),
new IdentityResources.Email()
};
...........................................................................
new Client
{
ClientId = "client",
ClientName = "SomeClient",
ClientSecrets = { new Secret("secret".Sha256()) },
AllowOfflineAccess = true,
UpdateAccessTokenClaimsOnRefresh = true,
RefreshTokenUsage = TokenUsage.ReUse,
SlidingRefreshTokenLifetime = 1200,
RefreshTokenExpiration = TokenExpiration.Sliding,
AccessTokenLifetime = 900,
IdentityTokenLifetime = 120,
AllowedGrantTypes = { GrantType.ResourceOwnerPassword },
AccessTokenType = AccessTokenType.Jwt,
AllowedScopes =
{
IdentityServerConstants.StandardScopes.OpenId,
IdentityServerConstants.StandardScopes.Profile,
IdentityServerConstants.StandardScopes.Email
}
},
Interesting fact is that RequextedResource from ProfileDataRequestContext has claims data, which I can use to figure out what claims user has requested. For example:
var claimsNames = new List<string>();
claimsNames.AddRange(context.RequestedResources.IdentityResources.SelectMany(r => r.UserClaims));
claimsNames.AddRange(context.RequestedResources.ApiResources.SelectMany(r => r.UserClaims));
context.RequestedClaimTypes = claimsNames;
But it seems to be hacky way. Does someone know why RequestedClaimTypes isn't populated automatically?
P.S Client is the postman with the following parameters