This happens to me frequently. I've also noticed that sometimes the "Did you mean [this]?" or "Search instead for [this]" don't show up anymore, which can be a big problem. As an example, it's difficult to find information on the company "Amazone" because Google insists on correcting it to Amazon. Usually putting things in quotes fixes it, but it's annoying when I know what I want to search for and Google keeps assuming I want something else.