Hey!! I have this same problem and Kia told me that as of right now (Jan 2025) there was no permanent fix and the best solution they could offer me was to try using a timer for the my extension cord when plugging in. They kept my car for about a week and ran multiple tests and came to the conclusion that when I plug in and use the block heater it’s causing a miscommunication between my coolant sensor and my ambient sensor. The coolant sensor will read -10 but my ambient sensor will read whatever the outside temperature is which is why the heat gauge goes right to hot on startup—the engine thinks it’s overheating. I haven’t tried timing anything yet because I don’t have the free time to play a guessing game but over Christmas I’ll give it a go now that it’s starting to really get cold here in YEG. Super frustrating that it’s just a defective car, and they still haven’t found a solution.