The big problem is disconnects, where the autonomous system gives up and demands that the human take over. A big question with Tesla is whether "Full Self Driving (supervised)" is really a Level 3 system. It's currently "full self driving until it screws up, then it's your fault". Not "full self driving and if there's a situation it can't handle, it pulls over and parks". This is a big problem.[2]

[1] https://www.sae.org/blog/sae-j3016-update

[2] https://www.kbb.com/car-advice/level-3-autonomy-what-car-buy...