This reminds everyone that even the top-notch engineers that work at Google are still humans. A bugfix that didn't really fix the bug is one of the more human things that can happen.
I surely make much more mistakes than the average Google engineer, and my overall output quality is lower but yet, I feel a bit better with myself today.
A top result in a Google search tells me: "According to 2016 annual report as of December 31, 2016 there was 27,169 employees in research and development and 14,287 in operations."
With that many people, it is unreasonable to flat-out assume that everyone who works at Google is top-notch. This kind of stereotyping is insidious in the labor-market for people who are otherwise excellent but do not have the magic fairy dust of Google sprinkled on them.
It is important to remember that no matter how impressive the machinery looks from the outside, everything eventually traces back to a human being typing some text in some editor with an imperfect model of how some lego pieces fit together.