2020 Prius Prime Corrosion on Hatch Opener Switch

This corrosion is on the small plate which just touches the backs of your knuckles when you open the hatch door. It's an often-reported issue, but perhaps by another description.

In our case, the car as delivered had no coating on that part - it was just bare metal. It started to corrode, I made a warranty claim, and took it to a body shop where the area was painted.

Now, less than two years later, rust is forming around the edge of the part and the paint is lifting. The car is out of warranty and the body shop says that nobody warrants paint jobs. They told me that they have seen half a dozen cases of this problem in the Halifax area.

I'm going to write to Toyota Canada about this, and I'd like to include a copy of the applicable Technical Service Bulletin. I found one for the USA covering my model year, and one for Canada which only goes up to 2018. Would anyone have a copy of the appropriate TSB ("Corrosion on the Back-Door Steel Reinforcement Panel Around the Switch and Rear Camera") for the Canadian market, applicable to the 2020 model year?

Any comments and advice about this would be very welcome.