I have a custom post-type called Auction.
I also have custom taxonomies called Auction Categories.
However, when I view a product that is more than one level of auction categories deep, the final category doesn't show up in the breadcrumbs.
Another part of my template uses
get_the_term_list( get_the_ID(), 'auction_cat', '', ', ', '' ); ?>
and lists all of the categories for each auction just fine