Mobile version, google what are you doing?

Question

Search Engine Optimization

Hello. Recently added a responsive design to my site. A couple of days later, Google sends me a message
"When your site was crawled by Googlebot for smartphones, we detected a significant increase in the number of URLs that return an HTTP 404 (page not found) errors."
There are many pages with 404 notes found for smartphones... We look at the pages that Google tries to index and gets 404:
1 m/questions/?qid=161776
2 m/questions/?qid=1117365
3 m/questions/?qid=882688
4 mobile/questions/?qid=129394
5 m/questions/?qid=214005
6 m/questions/?qid=732825
7 mobile/questions/?qid=209852
It looks like nonsense because the category "m" or "mobile" has never been on the site and most likely will not be. Google itself decided that such urls exist, went to them, naturally got my 404, then said that I don’t do anything for smartphone users. Is this normal or how can I explain it?

Answer 1

Many people have this problem. There are a bunch of threads here with similar questions.
Options 2:
1) Google itself has been looking for mobile versions of sites lately. Something is coming....
2) Somewhere/Someone has posted a link with /m/ and now Google is trying to index it.