Why did the deck on a 2019 Ford Fusion turn into powder as soon as I touched it?

Method 1: This has nothing to do with your solution or any other tinting-related issues. It’s simply a flaw from the manufacturers that is common in a lot of Fusion models. This problem should be taken up with the dealership. Tinters working on used Fusion models need to make a note of this and either not touch the decking, remove it completely, or explain the situation to the customer.