Auto machine runs at high pressure and wakes patient up in the night
This can happen when there is a mouth or mask leak and the auto machine increases the pressure to compensate for the leak, The increased pressure makes the leak worse and eventually the extra pressure wakes up the patient, sometimes with a dry mouth.
Usually pressing the Ramp button or switching the machine off and then restarting will solve the immediate problem, but it will re-occur again until the fundamental problem of mask or mouth leak is solved.