With no other substance involved besides the water, I don't see how this could happen. Say you put a vessel of hot water and a vessel of colder water in the fr

With no other substance involved besides the water, I don't see how this could happen. Say you put a vessel of hot water and a vessel of colder water in the freezer at the same time. If the hot water does indeed reach 32F before the cold water does, then there has to be an earlier point where their temperature versus time slopes cross, at which point their temperatures are equal. Once that point is reached, there's no longer any difference between the "hot" and "cold" water. Since the point of temperature equality can't be reached in negative time, the hot water can't possibly freeze sooner than the cold water that was placed in the freezer at the same time. So: given that the effect does, in fact, happen, there's some factor at work other than the water temperature. Some property of the container, perhaps? If the hot container loses its heat at a faster rate than the cold container, perhaps it ends up cooler than the surrounding water, and can continue to accelerate the freezing process beyond the point where the temperature slopes cross each other. That'd be my guess.