2021 Palisade Calligraphy 15,000 miles. We normally set the heat/air on 72 automatic and leave it alone. Recently during two trips while driving along about 50 miles from home, the temperature suddenly turns cold. Both times, we could turn it up to 78 and it would be about the same as it usually is at 72. But, the next time we drive it, the heat is 78. I checked the water level and it’s between the low and upper marks. Anyone have an idea why it’s doing this? I’m sure the dealer won’t be able to replicate this.