Loading an exported flag in Features crashes Drupal with WSOD

I have a very strange and repeatable problem with a flag I've created with 7.x-2.1. Loading the flag via an export (I'm exporting and deploying using Features) kills Drupal with the error

PHP Fatal error:  Cannot access property started with '\0' in /opt/my-site/drupal/sites/all/modules/contrib/flag/flag.inc on line 213

The cause turns out to be the exported flag.

It looks something like this:

>
$flags = array();
// Exported flag: "Mail Me On New Posts To This Group".
$flags['subscribe_group_content'] = array(
  '' . "\0" . '*' . "\0" . 'defaultValues' => array(
    'isOverridden' => FALSE,
    'overridesApplied' => FALSE,
    'ogContext' => FALSE,
    'fid' => '2',
    'content_type' => 'node',
    'name' => 'subscribe_group_content',
    'title' => 'Mail Me On New Posts To This Group',
    'global' => '0',
    'types' => array(
      0 => 'chapter_group',
      1 => 'dacountry_group',
      2 => 'region_group',
      3 => 'topic_group',
    ),
    'flag_short' => 'Subscribe me to emails for this group',
    'flag_long' => 'Send me mail on new messages',
    'flag_message' => 'You are subscribed to email notifications',
    'unflag_short' => 'Stop sending me email for this group',
    'unflag_long' => 'Stop sending me email notifications on new content',
    'unflag_message' => 'Email notifications have been turned off.',
    'unflag_denied_text' => '',
    'link_type' => 'toggle',
    'roles' => array(
      'flag' => array(
        0 => '11',
        1 => '7',
      ),
      'unflag' => array(
        0 => '11',
        1 => '7',
      ),
    ),
    'weight' => 0,
    'show_on_form' => 0,
    'access_author' => '',
    'show_on_page' => 1,
    'show_on_teaser' => 1,
    'show_contextual_link' => 0,
    'i18n' => 0,
    'module' => 'group_content_notification_system',
    'locked' => array(
      'name' => 'name',
    ),
  ),
  'isOverridden' => FALSE,
  'overridesApplied' => FALSE,
  'ogContext' => FALSE,
  'content_type' => 'node',
  'title' => 'Mail Me On New Posts To This Group',
  'global' => '0',
  'types' => array(
    0 => 'chapter_group',
    1 => 'dacountry_group',
    2 => 'region_group',
    3 => 'topic_group',
  ),
  'flag_short' => 'Subscribe me to emails for this group',
  'flag_long' => 'Send me mail on new messages',
  'flag_message' => 'You are subscribed to email notifications',
  'unflag_short' => 'Stop sending me email for this group',
  'unflag_long' => 'Stop sending me email notifications on new content',
  'unflag_message' => 'Email notifications have been turned off.',
  'unflag_denied_text' => '',
  'link_type' => 'toggle',
  'roles' => array(
    'flag' => array(
      0 => '11',
      1 => '7',
    ),
    'unflag' => array(
      0 => '11',
      1 => '7',
    ),
  ),
  'weight' => 0,
  'show_on_form' => 0,
  'access_author' => '',
  'show_on_page' => 1,
  'show_on_teaser' => 1,
  'show_contextual_link' => 0,
  'i18n' => 0,
  'module' => 'group_content_notification_system',
  'locked' => array(
    'name' => 'name',
  ),
  'api_version' => 2,
);
return $flags;

The issue is the truly weird

'' . "\0" . '*' . "\0" . 'defaultValues' => array(

If I edit out the part before 'defaultValues', everything works as expected. But this line in the export kills PHP deader than a doornail.

Not sure why this occurs, or how.