Switch not working in Meta Box Group

All plugins are up to date. I have two switch form fields in a meta box group. When I toggle one of the switches, the post gets saved just fine. When I leave both switches un-toggled and save the post, I get an error which reads: Warning: Invalid argument supplied for foreach() in /home/umcgot/public_html/wp-content/plugins/meta-box-group/class-rwmb-group-field.php on line 240

The switches work fine outside of the group.

Thanks for your help! -Brian

<?php
add_filter( 'rwmb_meta_boxes', 'prefix_register_meta_boxes' );
function prefix_register_meta_boxes( $meta_boxes ) {
    $prefix = 'umc_got_';
    $meta_boxes[] = array(
        'id'         => 'umc_got',
        'title'      => 'Game Of Thrones',
        'post_types' => 'umc_got_bracket',
        'context'    => 'normal',
        'priority'   => 'high',

        'fields' => array(
            array(
                'name'   => 'Group', // Optional
                'id'     => 'group_id',
                'type'   => 'group',
                // List of sub-fields
                'fields' => array(
                    array(
                        'id'        => 'jon_snow',
                        'name'      => 'Jon Snow / Targaryen',
                        'type'      => 'switch',
                        'style'     => 'square',
                        'on_label'  => '<i class="dashicons dashicons-yes"></i>',
                        'off_label' => 'Alive',
                        'class'     => 'umc_got_switch',
                        'columns' => 4
                    ),
                    array(
                        'id'        => 'daenerys',
                        'name'      => 'Daenerys Targaryen',
                        'type'      => 'switch',
                        'style'     => 'square',
                        'on_label'  => 'Dead',
                        'off_label' => 'Alive',
                        'class'     => 'umc_got_switch',
                        'columns' => 4
                    ),
                ),
            ),
        )
    );
    return $meta_boxes;
}
?>