default value not working

Hi,

The fields I created don't show or save the default values ​​quite often.
The following settings are one of them. Comment out id 'prd_checkbox_new' to see the defaults for the other fields. However, when id p'rd_checkbox_new' is enabled, no other field values ​​are displayed.

'fields' => array(
            array(
                'name'        => 'NEW label year',
                'label_description' => '',
                'id'          => 'prd_new_year',
                'desc'        => '',
                'type'        => 'text',
                'placeholder' => '2021',
                'std' => '2021',
            ),
            array(
                'name'        => 'NEW label text',
                'label_description' => '',
                'id'          => 'prd_new_text',
                'desc'        => '',
                'type'        => 'text',
                'placeholder' => 'label text',
                'std' => 'label text',
            ),
            array(
                'name'          => 'NEW label background color',
                'id'            => 'prd_new_color',
                'type'          => 'color',

                // Color picker options. See here: https://automattic.github.io/Iris/.
                'js_options'    => array(
                    'palettes' => array('#af3333', '#007333', '#006333')
                ),
                'std' => '#af3333',
            ),

            array(
                'name' => 'Show NEW',
                'id' => 'prd_checkbox_new',
                'type' => 'checkbox',
            ),
        ),

Please tell me how to display the default value.

Thanks and regards,
Yumikom