Bluff Charts incompatible with ajax

If I create a view with an exposed filter and ajax enabled in a block, the chart displays nicely with the filter above it. However, when I try to change the filter (I want to view a chart showing a different vocabulary), the chart disappears. Inspecting the source code, it got the right terms, but the counts all came up as zero. No javascript errors, and nothing in the Drupal logs. Here's the view code:

$view = new view;
$view->name = 'dped_charts';
$view->description = '';
$view->tag = '';
$view->view_php = '';
$view->base_table = 'term_data';
$view->is_cacheable = FALSE;
$view->api_version = 2;
$view->disabled = FALSE; /* Edit this to true to make a default view disabled initially */
$handler = $view->new_display('default', 'Defaults', 'default');
$handler->override_option('relationships', array(
  'vid' => array(
    'id' => 'vid',
    'table' => 'term_node',
    'field' => 'vid',
  ),
));
$handler->override_option('fields', array(
  'name' => array(
    'id' => 'name',
    'table' => 'term_data',
    'field' => 'name',
  ),
  'tid' => array(
    'id' => 'tid',
    'table' => 'term_data',
    'field' => 'tid',
  ),
  'nid' => array(
    'label' => 'Count',
    'alter' => array(
      'alter_text' => 0,
      'text' => '',
      'make_link' => 0,
      'path' => '',
      'link_class' => '',
      'alt' => '',
      'prefix' => '',
      'suffix' => '',
      'target' => '',
      'help' => '',
      'trim' => 0,
      'max_length' => '',
      'word_boundary' => 1,
      'ellipsis' => 1,
      'html' => 0,
      'strip_tags' => 0,
    ),
    'empty' => '',
    'hide_empty' => 0,
    'empty_zero' => 0,
    'link_to_node' => 0,
    'exclude' => 0,
    'id' => 'nid',
    'table' => 'node',
    'field' => 'nid',
    'relationship' => 'vid',
  ),
  'views_sql_groupedfields' => array(
    'label' => 'Group By Fields',
    'alter' => array(
      'alter_text' => FALSE,
      'text' => '',
      'make_link' => FALSE,
      'path' => '',
      'alt' => '',
      'link_class' => '',
      'prefix' => '',
      'suffix' => '',
      'target' => '',
      'trim' => FALSE,
      'max_length' => '',
      'word_boundary' => TRUE,
      'ellipsis' => TRUE,
      'strip_tags' => FALSE,
      'html' => FALSE,
    ),
    'empty' => '',
    'hide_empty' => 0,
    'empty_zero' => 0,
    'exclude' => '1',
    'id' => 'views_sql_groupedfields',
    'table' => 'views_groupby',
    'field' => 'views_sql_groupedfields',
    'relationship' => 'none',
    'views_groupby_fields_to_group' => array(
      'tid' => 'tid',
    ),
    'views_groupby_sql_function' => 'count',
    'views_groupby_fields_to_aggregate' => array(
      'nid' => 'nid',
    ),
    'views_groupby_field_sortby' => 'nid',
    'views_groupby_sortby_direction' => 'asc',
  ),
));
$handler->override_option('filters', array(
  'vid' => array(
    'operator' => 'in',
    'value' => array(
      '1' => '1',
    ),
    'group' => '0',
    'exposed' => TRUE,
    'expose' => array(
      'use_operator' => 0,
      'operator' => 'vid_op',
      'identifier' => 'X-Axis',
      'label' => 'Taxonomy: Vocabulary',
      'bef_filter_description' => '',
      'bef_format' => 'default',
      'optional' => 1,
      'single' => 1,
      'remember' => 0,
      'reduce' => 0,
      'bef_select_all_none' => 0,
    ),
    'id' => 'vid',
    'table' => 'term_data',
    'field' => 'vid',
    'relationship' => 'none',
    'override' => array(
      'button' => 'Override',
    ),
  ),
));
$handler->override_option('access', array(
  'type' => 'none',
));
$handler->override_option('cache', array(
  'type' => 'none',
));
$handler->override_option('use_ajax', TRUE);
$handler->override_option('items_per_page', 0);
$handler->override_option('style_plugin', 'charts');
$handler->override_option('style_options', array(
  'views_charts_series_fields' => array(
    'name' => 'name',
  ),
  'views_charts_x_labels' => 'name',
  'width' => '295',
  'height' => '295',
  'engine' => 'bluff',
  'type' => array(
    'bluff' => 'pie',
  ),
  'wmode' => 'window',
  'y_min' => '0',
  'y_legend' => 'Shares of Total',
));
$handler = $view->new_display('block', 'Block', 'block_1');
$handler->override_option('block_description', '');
$handler->override_option('block_caching', -1);