After the May update, InsideEVs reports there's a new paragraph in the Model 3's manual that reads:

"Caution: To avoid corrosive damage that may not be covered by the warranty, rinse away any road salt from the underside of the vehicle, wheel wells, and brakes. After cleaning the vehicle, dry the brakes by going on a short drive and applying the brakes multiple times."

The timing could, of course, be a coincidence as rinsing off road salt from under the vehicle is a smart move on any car, even with the levels of protection applied from the production lines on most cars now. However, the timing does make it look like Tesla knows there's an issue and is trying to give itself a level of protection legally. If it's a widespread problem and paint is rubbing off in those areas, Model 3 owners living in places with harsh winters where the road is often salted are going to develop problems quickly.