From the end of July through just a couple of days ago, Google has had this weird error for some sites in Google Search Console. In short, Google Search Console was reporting the wrong canonical URL for some pages. Yesterday, September 4th, it seemed like Google fixed the issue.
The issue was first reported by Rafael Martin back on August 4th, eventually he wrote it up in detail on LinkedIn. I highly recommend you read his detailed write up.
But in short, Google Search Console was reporting the wrong canonical URL for some pages. The canonical URL is the URL Google says is the main URL for a specific page. So if you have a page like this and you add parameters to it, or you have a mobile version or an AMP version, all with different URLs, you can specify which page you want Google to consider the main URL, not the alternate URL - that is called the canonical URL.
Rafael Martin said on August 4th on Mastodon, " In the GSC, the pages with the most links have radically changed. In my case, I have analyzed the first one with the most links (which, in principle, according to the structure of the site, should not have so many links). I check the pages that link to it, and most of them don't have a link to it (as example one that is a pdf without any links to there). I don't get it, it seems that google has mixed up some data and is missing out on search results."
He shared these two screenshots documenting the issue:
He was right, John Mueller of Google actually confirmed the...
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