A similar thing has happened with companies that go to great lengths to make sure they don't have any gender bias in their hiring process (no face-to-face during interviews, voice altering during phone interviews, etc.) only to find that they still selected more men than women. The conclusion, of course, is that they must be doing something wrong because it's simply impossible that they wouldn't be selecting a perfect 50/50 mix of men and women.

Similarly, I think imagine Google will find similar flaws with how these numbers were generated.