Hi Yumiko,
This issue has been fixed in the new version of Meta Box AIO 1.13.8. Can you please re-check the conditional logic for subfields? For example
add_filter( 'rwmb_meta_boxes', 'your_prefix_function_name' );
function your_prefix_function_name( $meta_boxes ) {
$prefix = '';
$meta_boxes[] = [
'title' => __( 'Post Meta', 'your-text-domain' ),
'id' => 'post-meta',
'fields' => [
[
'name' => __( 'Group', 'your-text-domain' ),
'id' => $prefix . 'group',
'type' => 'group',
'save_field' => 1,
'fields' => [
[
'name' => __( 'Text', 'your-text-domain' ),
'id' => $prefix . 'text',
'type' => 'text',
'save_field' => 1,
],
[
'name' => __( 'Textarea', 'your-text-domain' ),
'id' => $prefix . 'textarea_gzljad6ej2d',
'type' => 'textarea',
'save_field' => 1,
'visible' => [
'when' => [['group_text', '=', 123]],
'relation' => 'or',
],
],
],
],
],
];
return $meta_boxes;
}