Last week, we were on the A380 SFO-LHR flight in J (UD) forward cabin, and it felt as thought they were cycling the cold/hot settings.
Just when I was getting comfortable and felt the AC, it appeared that before I could dose off to sleep the circulating cool air stopped. And just when I was prepared to complain, I began to feel cooler again. Crazy no?
Eventually, I did manage to get about 4 hrs of some semi-sleep during the flight!