hrm. I've had my mya octagon for over a year and I am not experiencing this.
I also have a mya qt ( for about 4 years)- no issues there, and I had an acrylic mya (for 3 w/ no issues) and a ruby red star Mya for a littl eunder a year with no issues either.
I've never had any sort of "peeling" or chipping" issues with any of them.
Take a picture of it, so we can better see what is happening to your rig