Pathauto does not trigger on node_save when programatically creating nodes
We discussed on Drupal.org that not setting the $node->language property causes this issue to happen. Either setting $node->language = LANGUAGE_NONE or $node->language = 'en' should fix this.

Also using $node->path['pathauto'] = TRUE rather than $node->pathauto_perform_alias for Drupal 7.