WordPress：用户meta不会抓取PHP

Question

I am trying to get this meta data to display:

public static function user_register($user_id) {
    //The user_id is grabbed from wordpress and this is run after user 
    //registration, echo does display correctly the user_id as 806 (example)

    //$data = empty.. which makes no sense!!
    $data = get_user_meta ( $user_id , 'business', true );

    //Everything undernearth runs as it should..
    $grID = $wpdb->get_var("SELECT group_id FROM wp_groups_group WHERE name = '$data'");
    Groups_User_Group::create( array( 'user_id' => $user_id, 'group_id' => $grID ));
}

Some confirmations:
Yes! setting variable $data = "806"; does fix it!
However, this variable changes... I can't have a static string (806) for this. It has to be the current user.
The database is correct, there is a meta for business and the value is set (DB also seems to be fine)

user_id == 806 (confirmed with testing below)

public static function user_register( $user_id ) {
    if($user_id == 806){
        $data = "806";
    }
    $grID = $wpdb->get_var("SELECT group_id FROM wp_groups_group WHERE name = '$data'");
    Groups_User_Group::create( array( 'user_id' => $user_id, 'group_id' => $grID ));
}

Other scripts that I have tried replacing $data with:

$data = get_user_meta ( get_current_user_id() , 'business', true );

and

$usr = get_current_user_id();
$data = get_user_meta ( $usr , 'business', true );