I'm not sure how much of my information will appear with my username, but it's a Resmed Air Sense 10 Automatic. My pressure automatic 4 -6. Gel nasal pillows.
I've been using it religiously since June and have a great record. I am registered with Resmed My Air and have scored between 96-100 almost every night, with no leaks.
I have a good seal and only take it off perhaps once or twice per night.
My average incidents are between .1 and .5 per night.
My normal hours are from 7-8 hrs. per night. HOWEVER, on 3 different occasions lately, it has only logged me with 1 hr. 42 minutes, 1 hr. 50 minutes, and 1 hour 49 minutes. I have no explanation, as I have done everything the same each night. These off nights are no different from any other night, save the wrong info on my machine.
Each time, I went to bed before midnight and when I awoke and turned it off, it was still blowing air, so I know it was on in the morning. I know it was on when I went to bed, as I always check the pressure under the nasal pillow.
My local rep is out today, but based on past experiences, I'm not optimistic that she will know anything about it or care to find out what the matter is.
If other machines are doing the same thing, I'm not sure how an exchange will help, though, I think that is what she will suggest.
Any ideas are welcome.