Hi,
We understand you are getting the word “false” as part of your breadcrumbs pathway.
We would like some more information.
1. To clarify, you placed the php code into single.php, page.php, and some other archive page file?
This works on all your posts and pages?
2. As a test if you were to also place the code in your header.php file and then visit the page which has the template does the issue resolve?
If so you may need to add the code to your template file itself. If you do that does the issue resolve?
3. Can you confirm you are using WordPress 5.6.2? You can check by clicking on the W in the top left and selecting About. If you need to update, please check with your host provider.?Please know that if you are using an older version of WordPress Core you may experience unexpected behavior with Yoast.?This guide explains more:?https://yoast.com/why-we-dont-support-old-wordpress-versions/.
4. Are all your non-Yoast plugins and themes also updated?
5. We had another recent release. Can you confirm you are using the most recent Yoast SEO Premium, v15.9? If you update, does the issue resolve?