This time it returned relevant result for me too, I recall getting annoyed by it some time ago so maybe its not relevant example anymore.
Anyway, it happens all the time. Goole assumes that I mean something and I need to quote words trying to enforce my query. Pretty much every time when the returned results don't include the words I typed is a frustration for me. It makes it very hard to fix the query because I need to study every result instead of having no results or obviously low quality results.
It's especially hard when I'm not well versed in the subject, so I need to go through the results only to realize that these results are not about the thing I'm looking for.
BTW, I do less Googling these days. I would usually search Reddit, HN and StackOverflow directly from their websites as the search results would be from the expected domain and not too smart but just enough smart to correct typos etc. Also the filters work better.