Breadcrumbs displaying correctly for some products but not others

WP version current
plugins current and have all been turned off then activated one by one
Using current version of WooCommerce

Site is in development at https://162.144.16.45/~isolabe1/

Correct breadcrumb structure should be:

shop/category/subcategory/item

Displays incorrectly here: https://162.144.16.45/~isolabe1/shop/art/sea-urchin-sculpture-matte-white-2/

But correctly here:
https://162.144.16.45/~isolabe1/shop/jewelry/anchor-necklace/

What is causing the breadcrumbs to display correctly in some cases but not others? I have looked at permalink structure, menu organization, parent/subcategory selected (same for all) and everything else I can think of. I am perplexed.

Thanks in advance.