我的自定义查询可以工作，但在调试模式下，我会遇到以下错误：

Notice: Undefined offset: 0 in /storage/content/24/150624/mydomain.com/public_html/wp/mysite/wp-includes/query.php on line 2232 

<?php $term = get_term_by( \'slug\', get_query_var( \'term\' ), get_query_var( \'taxonomy\' ) ); ?>

<?php 
global $post;

$args = array(
\'tax_query\' => array(
array(
    \'taxonomy\' => \'machinecategory\',
    \'terms\' => $term,
    \'field\' => \'slug\',
    \'operator\' => \'IN\'
)
),
\'posts_per_page\' => -1,
\'post_type\' => \'machine\',
);

$my_query = new WP_Query($args); ?>
<?php if ($my_query->have_posts()) : ?>
<?php while ($my_query->have_posts()) : $my_query->the_post(); ?>
<?php the_title();?> 
<?php endwhile; ?>
<?php endif;?>

<?php wp_reset_query(); ?>