Errors on form validation if date field placed in sub-form.

Okay. Little summary.

Notice: Undefined index: field_date in date_combo_validate() (line 454 in sites/all/modules/contrib/date/date_elements.inc).
Notice: Undefined index: field_date in date_combo_validate() (line 455 in sites/all/modules/contrib/date/date_elements.inc).

And my date fields was empty...

If we look to the latest code we can found this:

  $item = $form_values[$field_name][$langcode][$delta];
  $posted = $form_input[$field_name][$langcode][$delta];

I get this errors on order edit form(drupal commerce).
Date field attached to customer profile.
So actually $item located in
$form_values['commerce_customer_billing']['und']['profiles'][0]['field_date']['und'][0]
instead
$form_values['field_date']['und'][0]

Same to $pasted variable!

To fix this we need to use ['element']['#parents'] and drupal_array_get_nested_value

Attached patch fix problem.