this whole thread seems to me to center around the water molecules separating out or freezing at 32F instead of the SOLUTION freeze point temperature. this is not true in a flowing system. the water molecules are going to stay in solution and not freeze out separately and collect in the coldest part of the system (evaporator).
i do not have any chillers that have a design evaporating temperature colder than the solution freeze point...that would be dumb and counter productive. i have run across systems that were improperly maintained and had an evaporating temperature lower than the solution freeze point (due to low flow rates) and they did occasionally make slush...but i believe that it was a solution slush, not a water slush and the glycol still a fluid.