Hello @nvlctur,
Thanks for reaching out!
There are a few cases where a link might not be recognized:
1) Only links from inside the WordPress post editor are recognized. This means that links from navigational bars, menus, sidebars, or footers are not recognized. If you do not have any links to those pages from the default content area of other posts and pages, but you have other internal links on your website pointing to that page (i.e. breadcrumbs, menus, header, footer, etc.), then it is safe to ignore that warning.
2) Links need to be in absolute form. This means that links need to include the full domain. For example,?https://www.example.com/page-a?is an absolute link, while /page-a/ is a relative link.
3) If you are adding your content using a page builder or shortcodes, Yoast SEO plugin may not be able to detect and analyze the content or images in some cases. In this case, despite you have some links on it, Yoast SEO could not be able to detect it. As a matter of fact, the Yoast Premium plugin only analyzes the default WordPress content areas like the title, URL, and main content box and WP editor. If you are adding your content through other plugin or theme content boxes, Yoast SEO for WordPress Premium won’t be able to detect it by default.
That said, if you are sure you have added the links, or you don’t want to add any as you think is it inappropriate in those pages or posts, you can safely ignore the warning. Google will be able to index your page as well.