So my only conclusion is the platens' are not high grade material, despite having the DeWalt brand.

So my advice for using the sander is - don't use it for corner or edge detailed work when the pressure is all on the front point of the platen. Read full reviewWhen I compare it to my dedicated B&D sander with the same platen profile, I have never had any melting issues and I worked the B&D as hard as the DeWalt and over many years. I bought a new DeWalt multi-tool mainly for cutting floorboards and into dry wall for boxes, but it came with a sanding head and I thought that was great. Because the DeWalt has a powerful motor the sanding platen fitted with rough grade paper really got through most of what I was using it for. But then I started doing door frames and therefore had to put a lot of effort into the hard-to-get corners. On the second night of sanding, when I went to replace a sanding sheet, I found that I had melted one corner of the platen which I cursed myself for doing (this melted off the Velcro surface), thinking I had been too hard and aggressive when sanding.