Actually, the topic of this question involves an important health care issue surrounding exposure to copper sources in varying conditions.
For example, in case of acidic drinking water with copper plumbing, to quote a 1980 article in Archives of Disease in Childhood:
The boy's copper toxicosis was attributed to the ingestion of water which had a high copper concentration. Although the family's well water contained little copper, it had a pH of 3.8-4.8, and dissolved copper from the domestic plumbing. Three explanations may be offered... Thirdly, he had been fed on cows' milk diluted with water, and it is known that the availability for absorption of copper in milk is greater than in other foods.
Generally, applying heat is known to increase the speed of chemical reaction and relatedly, increased copper poisoning is found in cultures employing copperware, especially in combination with common milk consumption, to quote a source:
Indian childhood cirrhosis:
One manifestation of copper toxicity, cirrhosis of the liver in children (Indian childhood cirrhosis), has been linked to boiling milk in copper cookware.
So, caution and education is especially required in environments with potential copper exposure involving acidic conditions, warming and apparently, foods (like milk), noted to promote copper accumulation.