As Gary said, the Norcold 1200 has a defrost cycle. I's on a timer. When we had a 1200 Norcold in our Monaco, I would turn the refer off and then back on once a day to avoid the defrost cycle because the 1200 was soooo finicky and a pain to keep cold.
Don & Mary
2019 Newmar Dutch Star 4018 (Freightliner)
2019 Ford Raptor