My question is better rephrased as "what is legally considered an accident that needs to be reported?" If the car scrapes a barricade or curbs it hard but the airbags don't deploy and the car doesn't sense the damage, clearly they don't. There's a wide spectrum of issues up to the point where someone is injured or another car is damaged.

And not to move the goalposts, but I think we should also be tracking any time the human driver feels they need to take control because the autonomous system did something they didn't believe was safe.

That's not a crash (fortunately!), but it is a failure of the autonomous system.

This is hard to track, though, of course: people might take over control for reasons unrelated to safety, or people may misinterpret something that's safe as unsafe. So you can't just track this from a simple "human driver took control".