Canonical Only in Rendered HTML
What This Means
Pages that contain a canonical only in the rendered HTML after JavaScript execution. Google can process canonicals in the rendered HTML, however they do not recommend relying upon JavaScript and prefer them earlier in the raw HTML. Problems with rendering, conflicting, or multiple rel=”canonical” link tags may lead to unexpected results.
What Triggers This Issue
This issue is triggered when pages only contain a canonical link in the raw HTML after JavaScript execution. For example:
https://www.getasky.com/technical-seo/ Does not have a canonical link element in the raw HTML, but after JavaScript execution, contains the below canonical link element:
<link rel="canonical" href="https://www.getasky.com/technical-seo/" />How To Fix
Include a canonical link in the raw HTML (or HTTP header) if feasible to ensure Google can see it and avoid relying only on the canonical in the rendered HTML only.