Why does Yandex bot constantly add a non-canonical page to the search?

Question

Search Engine Optimization

SEOs, dear! I need your help!
Maybe someone has met with something like this: I constantly see in the Yandex webmaster how non-conan pages either get into the search, then I fly out. And this happens to the same theme pages all the time. Here is what they write in the properties when adding a page:

"The page was included in the search because, during its crawling by the robot, its content was significantly different from the content of the page at https://site.com/blog/statia-1/ , which was specified in the rel="canonical" attribute in the source code. Correct or remove the canonical attribute if it is incorrect. The robot will track the changes automatically."

But the pages are the same... 100% identical. Everything works from under CMS WP and a separate page was not created. Canonicality appeared due to the addition of a slash at the end of the URL and the corresponding attribute is specified on the non-canonical page. Share your thoughts please.

Answer 1

Are redirects of potential duplicates properly configured and working? https://apollon.guru/duplicates/

Answer 2

I had this when I used the Yoast plugin, if you also have it, try to observe the situation without it.

Answer 3

This does not affect the search results, do not pay attention