Multiple frontend & nested values

Hi there!

I need to create multiple frontend forms that share the same custom fields. I have run a couple of tests with identical setup:

Test 1:

<?php
add_filter( 'rwmb_meta_boxes', 'your_prefix_function_name' );

function your_prefix_function_name( $meta_boxes ) {
    $prefix = '';

    $meta_boxes[] = [
        'title'      => __( 'Test 1', 'your-text-domain' ),
        'id'         => 'test_form_1',
        'post_types' => ['research'],
        'fields'     => [
            [
                'name' => __( 'Title', 'your-text-domain' ),
                'id'   => $prefix . 'post_title',
                'type' => 'text',
            ],
            [
                'name'   => __( 'A cloneable value', 'your-text-domain' ),
                'id'     => $prefix . 'a_cloneable_value',
                'type'   => 'group',
                'fields' => [
                    [
                        'name' => __( 'Option 1', 'your-text-domain' ),
                        'id'   => $prefix . 'option_1',
                        'type' => 'text',
                    ],
                    [
                        'name'   => __( 'Nested', 'your-text-domain' ),
                        'id'     => $prefix . 'nested ',
                        'type'   => 'group',
                        'clone'  => true,
                        'fields' => [
                            [
                                'name' => __( 'Option 2', 'your-text-domain' ),
                                'id'   => $prefix . 'option_2',
                                'type' => 'text',
                            ],
                        ],
                    ],
                ],
            ],
        ],
    ];

    return $meta_boxes;
}

Test 2:

<?php
add_filter( 'rwmb_meta_boxes', 'your_prefix_function_name' );

function your_prefix_function_name( $meta_boxes ) {
    $prefix = '';

    $meta_boxes[] = [
        'title'      => __( 'Test 2', 'your-text-domain' ),
        'id'         => 'test_form_2',
        'post_types' => ['research'],
        'fields'     => [
            [
                'name' => __( 'Title', 'your-text-domain' ),
                'id'   => $prefix . 'post_title',
                'type' => 'text',
            ],
            [
                'name'   => __( 'A cloneable value', 'your-text-domain' ),
                'id'     => $prefix . 'a_cloneable_value',
                'type'   => 'group',
                'fields' => [
                    [
                        'name' => __( 'Text', 'your-text-domain' ),
                        'id'   => $prefix . 'option_1',
                        'type' => 'text',
                    ],
                    [
                        'name'   => __( 'Group', 'your-text-domain' ),
                        'id'     => $prefix . 'nested',
                        'type'   => 'group',
                        'clone'  => true,
                        'fields' => [
                            [
                                'name' => __( 'Text', 'your-text-domain' ),
                                'id'   => $prefix . 'option_2',
                                'type' => 'text',
                            ],
                        ],
                    ],
                ],
            ],
        ],
    ];

    return $meta_boxes;
}

But my issue is that the nested field values are not saved across the form. So the option_2 saves in one form but does not save / update in the other. I tried changing the IDs incase of a conflict. Is this a bug or something I am doing wrong? Wanting to understand before going ahead and building a lot of form duplicates!

Many thanks,
Yasmine