That's an odd claim. Human failures are uncorrelated, but the Waymos all running the same software must be expected to fail in the same way, in the situations in which they fail. Which is why they often make the news; one Waymo stuck soon sees many of its brethren join it.

Don't humans fail in the same way too, broadly speaking? Wouldn't it depend on how you categorize failure?

If a Waymo failed because it missed a stop sign, and then another Waymo failed because it was confused about some strange markings on the road, is that not failing "the same way" in the same sense that a person failing to yield or driving drunk?