Fellow commenter JMC pointed me to this Microsoft article, where they explain what the old and new Windows Certificate of Authenticity stickers should look like. If you click on "More information" under "Preinstalled Windows COAs", you'll see a pop-up where the cycling image shows you my sticker. Here's a copy:
So I was wrong, it's not burning. But is does wear out. It seems some makers, like Compaq, are laminating it to protect it. I can tell you mine is getting worse every week. The hole itself is enlarging a little, probably because of the friction with my legs when I'm "Couch Working", and the heat is making the top and bottom sides peal. Let's hope Dell decides to laminate them it the future. As for me, case closed... until it falls off!