Puppet example showing default parameters on exported defined types aren't stored in the catalog

Catalog

{
  u'parameters': {
    u'ensure': u'present', 
    u'path': u'/data/test', 
    # Missing are job_name, server_name, backup_schedule
  },
  u'title': u'test',
  u'tags': [u'node', u'backup', u'testnode.localdomain', u'class', u'backup::job', u'job'],
  u'exported': True, 
  u'file': u'/home/puppet/production/modules/backup/manifests/init.pp', 
  u'line': 123, 
  u'type': u'Bacula::Job'
}

Example Manifests

class backup::common(
        $server_name, # internal server name clients should backup to
    ) {
    # common stuff like package installs
}

class backup::client(
        # Can be overridden per-client using hiera
        $backup_schedule='Weekly',
    ) {
    include backup::common
    @@backup::client {
        $::fqdn:
            # explicit parameters are stored in the catalog
            ensure => present;
            # Expecting omitted parameters to have default values resolved and stored in catalog.
            # This is not the case. Should it be?
    }
    @@backup::filesystem {
        'test':
            # explicit parameters are stored in the catalog
            ensure => present,
            path   => '/data/test';
            # Expecting omitted parameters to have default values resolved and stored in catalog.
            # This is not the case. Should it be?
    }
}

class backup::server(
        $config_dir='/etc/backup/conf.d',
        $storage_path='/data/backup',
    ) {
    include backup::common
    # Collect resources for things that should be backed up to this server
    # Since server_name is not listed explicitly above, it's not in the catalog
    # so these don't match anything!
    Backup::Client<<| server_name == $::backup::common::server_name |>>
    Backup::Job<<| server_name == $::backup::common::server_name |>>
}

define backup::client(
        $ensure=present,
        # Sensible defaults, expecting these to resolve on the exporter side and be stored in catalog
        $client_name=$title,
        $server_name=$::backup::common::server_name,
    ) {
    file {
        "${::backup::server::config_dir}/${client_name}.conf":
            # Template uses parameters that the client should provide,
            # scope lookup to get at $::backup::server variables
            content => template('backup/_client.conf.erb');
    }
}

define backup::job(
        $ensure=present,
        # Sensible defaults, expecting these to resolve on the exporter side and be stored in catalog
        $job_name=$title,
        $server_name=$::backup::common::server_name,
        $backup_schedule=$::backup::client::backup_schedule,
        $path='/home',
    ) {
    file {
        "${::backup::server::config_dir}/clients/${title}.conf":
            # Template uses parameters that the client should provide like backup_schedule
            # scope lookup to get at $::backup::server variables like storage_path
            content => template('backup/_client.conf.erb');
    }
}