I buy the European mugs from printerowners as they are supposed to be the best, but twice now I've had customers come back and say the base of the mug has come off. It is like someone has sliced through the mug just above the base and it seems like the crack appears when it is first filled with hot water. No injuries but obviously a safety issue. Has anyone else had this or could it be something I'm doing wrong? I reported it to the sales people the first time and they said it was a one in 500,000 chance but looking more like a 1 in 500 chance to me.