更新角色时出错

I have an issue with one of my projects, as soon as I try to update a role I got the following error.

The value in "Role Name" is already being used.

When I am editing/updating the role, the role name shouldn't be validated. Why is this happening?

I've looked into the controller and the model code and it just uses the regular code.

Controller:

if ($type == 'insert') {
    $id = $this->role_model->insert($data);
    $return = is_numeric($id);
} elseif ($type == 'update') {
    $return = $this->role_model->update($id, $data);
}

Model:

public function update($id = null, $data = null)
{
    // If this role is set to default, then set all others to NOT be default.
    if (isset($data['default']) && $data['default'] == 1) {
        $this->db->set('default', 0)
                 ->update($this->table_name);
    }

    return parent::update($id, $data);
}

Changed the validation rules as suggested by Kisaragi

protected $updateValidationRules = array(
    array(
        'field' => 'role_name',
        'label' => 'lang:role_name',
        'rules' => 'required|trim|max_length[60]|unique[roles.role_name,roles.role_id]',
    ),
);

to

protected $updateValidationRules = array(
    array(
        'field' => 'role_name',
        'label' => 'lang:role_name',
        'rules' => 'required|trim|max_length[60]|',
    ),
);

Thanks a lot.