HDJ 500 White, dye coming off the over ear foams

Hi, hope someone can help. My head phone are 18 months old, very light home use and over the last couple of weeks noticed that the over ear part of the headphones has started to become sticky and when the headphones are put down, a white paint type substance comes off over the table and my hands. It's quite difficult to get off like a paint.

Anyone else had this issue?

Paul