According to the IIHS and Consumer Reports, the problem lies in the fact that due to the swap to the camera-based system, certain safety features such as automated emergency braking and forward-collision warning will be temporarily unavailable or limited at the time of delivery. (Tesla's own blog post about the change only mentions limits on lane-keeping assist, and that lane-departure warning and Tesla's summon features might not be available.) To make CR's Top Pick list, a car has to have collision warning and emergency braking with pedestrian detection as standard; while this lowers the Model 3's scores it's still recommended, though the Model Y has a lower score.
The National Highway Traffic Safety Administration is also making changes because of Tesla Vision. Model 3 and Model Y EVs built after April 27, 2021, will no longer receive the agency's check mark for automated emergency braking, forward collision warning and lane-departure warning. According to Consumer Reports, this change was made after Tesla informed NHTSA about the camera system.