Pages are long gone, but Search Console shows them as an error?

Question

Search Engine Optimization

Once upon a time there was a website. Nobody removed it from the index, but simply created a new site with different url addresses (there was no seo specialist). Then all the old url addresses that led to 404 pages were removed from the index. But the search console still throws an error on those old yurls like 404 pages. Why? Are they not in the index? I am attaching a screenshot...

Answer 1

Kind!
Firstly, I would like to ask everyone at once, why are you all clinging to such trifles as 404? If you yourself killed the page, why worry about it? Well, it doesn’t exist and doesn’t exist, even though Search Console draws a grave cross in itself ...
Secondly, the HTTP code 404 does not mean at all that the page is no more. 404 means Not Found. Today "I couldn't," tomorrow I "shmogla". The algorithm for some time, as it were, protects the page from being permanently deleted from its database. Here is a bot from time to time and tests, suddenly the page will be unexpectedly found. Therefore, its behavior and error display is quite reasonable.
And if you want to say goodbye to the page forever, answer the bot immediately with 410 Gone.