Never had an issue with defrost or heat on my 2024 Leaf until I had the recall P4A17 applied. At the last cold snap, the heater worked fine for about 15m and than stopped working, just blowing cold air. I switched it off and waited a bit, switched it back on and it worked again. Called my local Nissan dealer and they said that they are aware of the issue and Nissan working on a fix. Happened again today 11 Feb. another cold snap, 12F when I left the house. Heater worked fine. Again after about 15m only cold air.