Those are "oopses", as someone who used to work at Mozilla called it in some article. If MS were to phone Google about it, they'd hear "oops, our mistake, we'll fix it asap."

And it'll happen often. An oops every few weeks. Every oops bleeds users to Chrome. Everytime a googler says "just a mistake" and they might not even be trying to be dishonest at it.

It's Google's corporate structure that enables this.