I recently noticed that on my 19 as well. It's very faint right now, but I'm guessing a few more transformations will make it worse. Also rubbed off some black paint from the leg part, but that is fully my fault as I was displaying it on top of a Flightpose stand and the rubber was unfortunately placed on that part. So careful guys if you plan to display using Flightpose. But I still love this toy, and currently in love with Fighter mode!