[keycloak-user] OpenID Connect: userkey instead of username

[Tech]

Dear experts,

we are working with an application that implements with a plugin OIDC.

What we detected is that when we run the authentication for a local user
present into Keycloak, the remote username appearing on the application
is the Keycloak's userKey instead of the Keycloak's username.

Is there anything that we should do to retrieve instead the username?

Thanks!