I will go with Freezup. Though the coils will not freeze that fast. The sensor (if such is present and in most models it is) is supposed to shut the compressor down BEFORE it freezes.
Option 2.. and just now I'm looking at option 2 (It's just to my right above me) the unit is not working, loss of refrigerant in my case.
I turn it on, it runs for a few mintues (no cold) and then since that same sensor says "Hey, I'm still hot" it shuts down.. COMPLETLY in this case, Blower and compressor both.. Then after a time out it tries again, Same results, New unit at technician, Adapter to mount it not in evidence, I'm going to self-adapt as soon as I can convince tech to put the upper unit on.