"handle_multiple_relationships" throws an error when no objects were found

When searching for multiple relationships with WP_Query, no error occurs if at least one search result exists.

However, if the search result does not exist, the following error occurs:

Warning: array_unique() expects parameter 1 to be array, null given in /var/www/html/wp-content/plugins/meta-box-aio/vendor/meta-box/mb-relationships/inc/query/query.php on line 193

Warning: implode(): Invalid arguments passed in /var/www/html/wp-content/plugins/meta-box-aio/vendor/meta-box/mb-relationships/inc/query/query.php on line 194

Temporarily, I'm preventing the error by adding the following code to the end of the function:

if (empty($merge_object_ids)) {
    $merge_object_ids = '-1';
} else {
    $merge_object_ids = array_unique( $merge_object_ids );
    $merge_object_ids = implode( ',', $merge_object_ids );
}