Sometimes a manufacturing defect can occur. This looks like 'bubbling' under the surface of the non-stick and is caused by particles of dust being trapped between the cookware and the non-stick, although this is very rare. Most other causes of non-stick peeling are due to metal utensils being used on the non-stick cookware which damages the surface. Wooden or nylon headed utensils should always be used. Another reason maybe that the wok has been heated without any oil.