Steps to reproduce the issue

Install a Joomla site & register in in the Google Search Console.

Expected result

Google Search Console should be able to validate the breadcrumb structured data on the site (to be able to list it in the rich search results).

Actual result

All the pages of the site are listed in the Google Search Console under breadcrumbs as a "critical issue" with the explanation that "Invalid items can't be used to generate rich results on Google."

System information (as much as possible)

I have 13 Joomla sites and Google Search Console has listed all of them and all of their pages as "Invalid" in their breadcrumb structured data. I am currently using Joomla 5.3.1. Upgrading to 5.3.2 does not fix this issue.
I am using YooTheme as a template, but the developers have verified that the issue is not caused by their template.
I am not using any 3rd party plugins or components.
Specifically, it says the pages are Missing field "itemListElement."
As an example, it says that the following entry is an "Unnamed item": "breadcrumb":{"@id":"https://www.sitename.com/#/schema/BreadcrumbList/17"}}

Additional comments

This issue was previously reported, tracked & closed (but not fixed) beginning Apr. 3 on GitHub here: #45277