The canonical URL can be found using the 'info'
To find out which URL is canonical for Google, you can use the 'info:' operator. This advice gave the representative of Google Search John Mueller during a regular hangout for webmasters.
Sometimes Google shows in the search results URL that is slightly different from the actual url. To understand this situation will help the operator 'info:'.
Type 'info:' before a URL and see what URL shows in the search results. Sometimes such a situation is possible that a search for a specific URL and search with the 'info:' operator return a different URLs. The 'info:' URL we use for indexing. This suggests that Google scan the content, but not at the specified URL. From a practical point of view, everything is fine. However, this complicates things like analytics, since you can't see the exact number of pages in the Search Console.
Therefore, in this case, I would have thought why Google chooses a different URL and also how to change the structure of the site for this URL Or would have tried to find references that are indexed by Google, and corrected the situation. Perhaps internally you are referring to both versions of the page. If you simplify the internal structure of the website and focus on your desired page, then we switch to her. Thus, it's not a critical error
Listen to his answer, starting at 9:35 in the video below: