Copy Custom Fields to All WPML Translations on Save

$wpide_keys = array( 'price', 'sku', 'latitude', 'longitude' ); // Meta keys to copy.

add_action( 'save_post', function ( $post_id, $post ) use ( $wpide_keys ) {
    static $running = false;

    if ( $running || ! defined( 'ICL_SITEPRESS_VERSION' ) || wp_is_post_revision( $post_id ) || wp_is_post_autosave( $post_id ) || ! current_user_can( 'edit_post', $post_id ) ) {
        return;
    }

    $type    = apply_filters( 'wpml_element_type', $post->post_type );
    $details = apply_filters( 'wpml_element_language_details', null, array( 'element_id' => $post_id, 'element_type' => $type ) );

    if ( ! $details || ! empty( $details->source_language_code ) || empty( $details->trid ) ) {
        return; // Not an original post.
    }

    $translations = apply_filters( 'wpml_get_element_translations', null, $details->trid, $type );

    if ( empty( $translations ) || ! is_array( $translations ) ) {
        return;
    }

    $running = true;
    foreach ( $translations as $translation ) {
        $target = (int) $translation->element_id;
        if ( $target === (int) $post_id ) {
            continue;
        }
        foreach ( $wpide_keys as $key ) {
            if ( metadata_exists( 'post', $post_id, $key ) ) {
                update_post_meta( $target, $key, get_post_meta( $post_id, $key, true ) );
            } else {
                delete_post_meta( $target, $key );
            }
        }
    }
    $running = false;
}, 20, 2 );