When logging types of issued claims, duplicates are logged.

[Nwoaah]

When the profile service fetches a user with multiple claims of the same type, the logging process duplicates them at the 'information' level.
https://github.com/DuendeSoftware/products/blob/97927d92196d2386c95e60fd0a4e72e27c300cd2/identity-server/src/IdentityServer/ResponseHandling/Default/UserInfoResponseGenerator.cs#L95

Log example:

[Duende.IdentityServer.ResponseHandling.UserInfoResponseGenerator] Profile service returned the following claim types: sub d:tntnm d:mid d:cid d:ver d:sec preferred_username name d:unuid d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr d:obr

[wcabus]

It's perfectly possible, as you mention, for users or ClaimsPrincipals to have multiple claim values for a given claim type. As a side effect, the UserInfoResponseGenerator mentions the same claim type more than once.

The development team is considering combining these claim types into a single mention (e.g., d:obr (41)). We will move this issue into the feature request section.