Re: hotpont Aquarius DWF30
Not being fully au fait with the chemical reactions involved I cannot give chapter and verse. Save to say that the black material is bitumen based, and does naturally become brittle and flaky with age and exposure. The heat generated by the machine will have some effect as well.
I can assure you that we see many thousands of these machines and after a few years all of the backs look a little worse for wear, nothing at all to worry about.
Jim.