Dear Claudio,
One reason for not getting immediate feedback is that you are asking a question about an old release, that we have not around anymore in action. Many things have changed in the user management in 5.10 (Antonio cleaned up much of this, the usage of util_memoize was greatly reduced for scalability reasons).
The second reason is that you are directly modifying a value in the database, which causes very likely cache inconsistency. This is no usage scenario of the system. The proper call after changing user data in the DB is to issue
acs_user::flush_user_info -user_id $user_id
In case you want to support this kind of direct updates to the DB for user_ids in your system, you might consider adding this line toauth::check_local_account_status or auth::get_local_account_status, that's better than duplicating this logic.
