It depends on your relationship with your dealer, they might swap the button free of charge. They have redesigned the start button a few years ago as the initial design had a flaw where the N letters where peeling.
I had this issue with my old 2014 GTI and after 2 years the button has been replaced under warranty although my dealer said that it is a "goodwill gesture" as it is considered wear and tear. The replacement button was the redesigned model where the N letter had the sharp edges joined to avoid peeling. The new GTI 2016 came with the new designed button so no issues so far.