[0xADEADBEE]

This happened to me just this week! I was trying to find a specific Onion article, so I searched various permutations, many of them including "the onion" which wasn't respected in the result output. I was absolutely furious that the one escape hatch I have to ameliorate bad searches was taken away from me.

Give it a try - I run CookieAutoDelete so it is 'theoretically' a clean search each time if that makes any difference.

[Umofomia]

I don't know whether this is necessarily the cause of your issue, but I discovered one reason why it doesn't always work. On mobile Safari, iOS ends up inserting smart quote characters rather than straight quotes when you type them. Google ends up ignoring the smart quote characters. To work around this, I have to hold down the " button to explicitly make the keyboard insert the straight quote character.

[JoeSmithson]

Are you saying that it was returning pages that didn't contain the phrase "the onion", or just weren't articles from The Onion? What was the exact search term?

[CharlesColeman]

Does that happen for words that aren't likely stopwords?