Form API #states not working properly

Hello! I wanted to check if anyone has experienced this issue. In Drupal 7, the following code hides the 'settings' textfield when you first load the page, until you click the toggle_me checkbox. Then it's shown (expected behavior).  In Backdrop, the textfield is not initially hidden -- it gets hidden only after you check and then uncheck the toggle checkbox.  Is this a bug? Where should I report it?

$form['toggle_me'] = array(
  '#type' => 'checkbox',
  '#title' => t('Tick this box to type'),
);
$form['settings'] = array(
  '#type' => 'textfield',
  '#states' => array(
    // Only show this field when the 'toggle_me' checkbox is enabled.
    'visible' => array(
      ':input[name="toggle_me"]' => array(
        'checked' => TRUE,
      ),
    ),
  ),
);