[fiblye]

>it's because the page they are looking for does not exist.

I could see that argument holding water if other search engines didn't give me precisely what I searched for. Google just simply tries to be smart and assume I'm looking for something other than what I input, while completely ignoring my input and replacing it entirely.

[londons_explore]

Give a few examples of it.

Theres a good chance whatever page you were after had a robots.txt excluding googlebot.