So I had this meta-box:

piklist('field', array(
  'type'    => 'group',
  'field'   => 'features',
  'label'   => 'Features',
  'add_more'=> true,
  'fields'  => array(
    array(
      'type'    => 'text',
      'field'   => 'title',
      'label'   => 'Title',
      'columns' => 12
    ),
    array(
      'type'    => 'textarea',
      'field'   => 'description',
      'label'   => 'Description',
      'columns' => 12,
      'attributes'  => array(
        'rows'        => 4
      )
    ),
    array(
      'type'    => 'file',
      'field'   => 'image',
      'label'   => 'Featured Image',
      'columns' => 12
    )
  )
));

Great! I then added this:

array(
  'type'    => 'radio',
  'field'   => 'image-alignment',
  'label'   => 'Image Alignment',
  'columns' => 12,
  'value'   => 'bottom',
  'list'    => false,
  'choices' => array(
    'top'     => 'Top',
    'center'  => 'Center',
    'bottom'  => 'Bottom'
  )
),

Almost great! I had 3 instances in the group before adding that field. Upon adding the field it showed up for only the first instance. If I add new instances they have the new field, but instances 2-3 have no chance of me setting a value for them. That means I have to make a new instance, copy/paste the stuff over, and remove the old. Not a big deal, but definitely a bug.

And in the spirit of the day 🙂 :