Canonical only found in rendered DOM
This means that the URL in question has a canonical element which is only present in the rendered DOM, and is not present in the source HTML.
Why is this important?
When assessing pages to include in their index, Google make an 'initial pass' of a page using only the source HTML (also called the 'response HTML'). As such, it is unwise to provide differing indexing signals in the response and rendered HTML (i.e. robots, canonicals,hreflang, etc...)
What does the Hint check?
This Hint will trigger for any internal URL which contains a canonical link element in the HTML when Sitebulb renders it using headless Chrome, but is NOT present in the source HTML.
Note: this Hint is only checked if the Chrome Crawler is selected during the audit setup.
Examples that trigger this Hint:
Consider the URL: https://example.com/page-a
The Hint would trigger for this URL if it had a canonical link in the <head> when rendered;
yet no canonical link element when not rendered.
How do you resolve this issue?
Google have stated categorically that the rendered canonical is not taken into account, so relying on it for indexing purposes would be unwise.
Google do caveat their statement by saying, 'if you really have to do it, then do it this way':