Sorry, I realise that this is a bit of tail chasing, but when you went into Nano to manually switch on the compressor, did Nano report that compressor was already on? I am guessing it said off.
Next time it does this can you write down the status of pump, pressure switch, and over temp switch before you change anything?.
It could still be an intermittent pressure switch or, less likely, the temp sensor.
Although, I would think that if either of those were bad, the ECU would not allow the Nano to turn on the pump?
Of course, intermittent faults are a bugger to track down, which is why I am asking previously answered questions......Looking for you to catch a different reading.
If, when you switch on the pump with Nano, as you said, the suspension immediately begins to rise, and stays up, I am thinking that the compressor is fine.
Mine was doing much the same thing, and it was a faulty relay. It could be an intermittent connection on the PCB of the fuseboard as well. They do fail.