I have a custom form that uses password_confirm element. During validation step, $form_state['rebuild'] is set, and so, the form is re-processed. When this element is re-processed, however, the settings are not added because of this part:
<?php
static $already_added = FALSE;
if (!$already_added) {
$already_added = TRUE;
$element['#attached']['js'][] = array('data'=> $js_settings, 'type'=> 'setting');
}
?>As this funcion is being called a second time in the same request, the settings don't get added, which causes a JS error. I'll work on a patch to fix this.