Decreasing pressure graph VAuto?

[permabear]

This morning when I checked Oscar I happened to see my pressure graph decreasing throughout the night. My pressure settings were 9.6/4.0 fixed (VAuto mode for registering FL), but the pressure graph shows both IPAP and EPAP decreasing all the way to zero in a straight line. 

I don't remember experiencing anything strange at awakening and both AHI and FL look great. I assume the actual pressure remained at setting levels, but why would the pressure graph act this weird? I checked it out for another 30min (07.00-07.30) but nothing to see.

Is this something that looks familiar to you? Maybe a software bug? Or even a sign that the machine's end of life is approaching? I bought the machine 2nd hand about 2 weeks ago and it has about 7,000 run hours. For the last 2 weeks it has run very smoothly.

   

[pholynyk]

That's very curious. Also your second session looks like it is in CPAP mode. I'd like to take a look at your SD card data. Please make a zip copy using Help->Troubleshooting->Make zip copy.... Please put your forum name in the file name, and upload it to Gideon's Dropbox: https://www.dropbox.com/request/6VeFzBXa4qZ37EgphL5b

Thanks.

As an aside, 7000 hours is nowhere near the life of a CPAP machine; mine has over 18000 hours and going strong.

[permabear]

Just uploaded the .zip file.
Thank you for taking a look at it!

[permabear]

The Oscar version might have something to do with it. When I downgrade to version 1.2.0 the pressure graph won't show any pressure at all. 

   

After I upgraded again to 1.3.0 I got the graph I posted earlier today. 

   

It's curious indeed. 
Looking forward to your comments!

[Gideon]

Got it.
Phil, you know where.

[pholynyk]

Got it! And here's the problem - a data error in the last value of the three pressure values:

Code:

82933: Debug: Failed to add last event -1.2 "Fri. Oct. 29 06:20:51 2021" Pos: 14279
82934: Debug: Failed to add last event -20 "Fri. Oct. 29 06:20:51 2021" Pos: 14279
82934: Debug: Failed to add last event -0.125 "Fri. Oct. 29 06:20:51 2021" Pos: 14279

 I thought I had fixed a similar problem, so I'll have to look into why this is different, or why I substituted zero instead of the previous value. 

This should be an intermittent error, and it seems to only show up when the machine is set for constant pressure.

[permabear]

Thank you so much. So it has nothing to do with the machine itself? This morning a decent pressure graph showed up again, so it seems to be intermittent indeed.