Anyone else getting ridiculous reports about pages not being found by Google?

It has been going on for some time now. Every now and then Google spews out a list of pages that it cannot find on my site. I am managing about 30 web sites spread across 2 servers. But even though they are separate websites and each has a unique domain name, Google is looking for pages that do not exist. The most obvious example /wp-admin/ which only exists on 1 in 30 sites.

Now I do recall a little while back that Google was starting to treat all aliases of a domain as the same site, which may seem clever to complete a idiot, but only one of my domains are using aliases.

I have been pondering about how such a thing can happen and wondering if someone has scraped one site and somehow submitted it as all of my other sites. But that would be impossible, right? Or it could be that getting indexed is a lot easier than what everyone thinks... if people are typing bad links into their address bar and Google is spidering those pages as if they exist, then we have a huge problem, and one that can damage everyone's site reputation. In the past I have found my test pages through search of their content... pages not linked to web and only visited once or twice by members of my team.

Other common errors are about canonical links... http vs https. All sites are https and submitted as https. In fact most redirect to https. So why would Google be spidering http pages and then complaining about canonical mismatches?

Or are these just more examples of Google's "superior" but broken technology?

[edited by: not2easy at 2:59 pm (utc) on Jun 6, 2024]
[edit reason] split thread cleanup [/edit]