Can't retrieve name from Sign In flow

We've just implemented Apple Sign In for bubble.is as a plugin according to the documentation.

(https://developer.apple.com/documentation/sign_in_with_apple/sign_in_with_apple_js/incorporating_sign_in_with_apple_into_other_platforms).

The login is working fine, but we can't retrieve the name, even if the purpose, set in scop is only "name".

what we receive:

{ "state": "EN", "code": "c10ab6**********************Ckggusd4UAdj-A",
 "id_token": "eyJraWQiOiJBSURP*****UOQ",
 "user": "{\"email\":\"********\"}" }