'Add ice' is only required for off-the-grid fridge during winter

I'm experiencing the same. No mods, just base pc game with some dlc's. I'm trying to use the geothermal lot trait to make money and allow my sims to swim during winter, but live completely off the grid otherwise. I have the option to make all refrigerators stop using the utility, but the ice doesn't melt at all. It's currently winter in my world, but we've lived through summer and fall this way.