The water pulled some of the sugar out and the lacto-bacteria started souring it. Try making a sour beer. I don't like them, but some people do and nothing survives the boil.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk