Hi Paul
My mugs are (and have been) used every single day without any problem at all, likewise I have had one since they were first available at a LEM a couple of years ago. Mine are also subject to the daily round in the dishwasher.
The mugs that flake tend to be the ones that have a thermal coating (change colour with heat), and these are not that kind of mug. I believe these mugs are simply screenprinted straight on to the glaze and I am at a loss to see how this could have occur.
Maybe it was a single rogue mug that had got into the system, perhaps it had been coated with something before being printed and had not been noticed. I do have some experience in this field as I used to be involved in a printing business.
Still, I guess it's better to issue a warning...
Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.”... Douglas Adams 1952 - 2001