Currently, in the Manage tab of one's profile, there's an entry in the log for when the user was approved, but there should also be one for when the user was created:

After discussing this with @valerio.bozzolan, it seems like the issue is that creating a user does not currently employ a transaction (xaction). So it might be necessary to create a new transaction in src/applications/people/xaction/, and/or modifying controller/PhabricatorPeopleNewController.php to use transactions.