An important test. Unplugging the device could be resetting some internal switch or timer.
That’s a good suggestion. After using my microwave oven for a while the controller gets into a bad state, cycling on and off (doesn’t appear heat related). Has done this for years. Unplugging it for a few seconds clears the problem. The air cleaner might have a similar fault.
Also, checking to make sure that the hot/neutral/safety ground in the outlets/power distribution are truly connected properly seems advisable.