Attributes not used when search is anonymous

[mvalois]

We have configured our LDAP module of our Matrix server like this :

modules:
  - module: "ldap_auth_provider.LdapAuthProviderModule"
    config:
      enabled: true
      mode: simple
      uri: 
         - "ldaps://xxx:636"
      validate_cert: true
      base: "ou=users,dc=xxx.internal,dc=local"
      attributes:
        uid: "uid"
        mail: "mail"
        name: "cn"
        
      filter: "(&(|(objectclass=xxx))(|(memberof=cn=user,ou=groups,dc=xxx.internal,dc=local)))"
      group_filter: "(&(|(objectclass=xxx)))"
      allow_empty_password: false

However we observe that uid, mail and cn are not retrieved from the LDAP server, while they are retrieved when we set bind_dn and bind_password.

Is it expected?
Is it possible to do anonymous requests and still retrieve attributes for mapping?

Thank you,