Some subcategories not working on custom portfolio sort

You can use below code: 

$args = array(
    'type'                     => 'product',
    'child_of'                 => 0,
    'parent'                   => '',
    'orderby'                  => 'term_group',
    'hide_empty'               => false,
    'hierarchical'             => 1,
    'exclude'                  => '',
    'include'                  => '',
    'number'                   => '',
    'taxonomy'                 => 'product_cat',
    'pad_counts'               => false
);

$cats = get_categories( $args );