It's not obvious that mineral water after boiling will contain something bad. There are all sorts of minerals in food and we boil it and eat it. There is no information on the bottle that it shouldn't be boiled either. Also, not every mineral water acts like that, just some, don't know what differs them yet. And I never said I use coffee machine..
You also don't know what happened with that water, you are just a typical forum loser that wanted to make someone feel stupid to feel better with yourself, without giving any valuable information.