You can't compare "exposed" pink stuff freeze status, when the container is subjected to moving air across the surface. That produces a "wind chill" factor, which rapidly lowers the temperature of the medium as the ambient temperature drops.
My observatoon; -50 degree burst protection, Peak brand, still in liquid state at -5 F in protected location.
This sure is sounding like a product stated quality issue. Otherwise, why would the same stated -50 burst rated pink stuff, have different states of consistancy (totally liquid vs slushy) when the temperatures are what is being observed.