MultilingualPress copy post meta GTIN field from Product Feed PRO ELITE

functions.php

<?php
add_action('multilingualpress.metabox_after_relate_posts', function($context, $request) {

    // get post meta value from source site
    $ProductFeedELITEGtinValue = (string)$request->bodyValue(
        '_woosea_gtin',
        INPUT_POST,
        FILTER_SANITIZE_STRING
    );

    // switch to remote sites and save post meta
    $remoteSiteId = $context->remoteSiteId();
    $remotePostId = $context->remotePostId();
    switch_to_blog($remoteSiteId);
    update_post_meta($remotePostId, '_woosea_gtin', $ProductFeedELITEGtinValue);
    restore_current_blog();
}, 10, 2);