What could be going on here?

[justMongo]

I'm going to split the baby in half (like Solomon.) I think a talk with the doc is first order of business.
It's possible that some periodic breathing is going on.
The flow diminishes in amplitude followed by a recovery breath.
With no correlating flow limitation, it would seem something involving the central respiratory drive.
Likely not a serious problem -- but disruptive to sleep architecture.
Good that the OP indicates a recent sleep study with no RERAs or CA.

I'm guessing the doc will agree to switch to fixed pressure.

[bayareacpap]

Wow - thanks to everyone for your advice, personal experiences, and research etc. This is all very helpful as I was so very tired but now feel really well rested (3rd day). I will definitely circle back with questions as I monitor my progress/numbers and will definitely circle back with the doc at some point about the pressure changes and breathing patterns. Thanks again for all of the great support!

[MobileBasset]

The graphs look normal to me. I have those same hiccups sprinkled among miles of smooth breathing. We are animals not machines. Even my dogs frequently have little breathing derflugalties.

I agree with Ghost about your sensitivity to the APAP. Set the auto minimum at your good constant pressure and let it go 3cm above. That's how I run mine. If you still don't feel as good as the CPAP then reset it to CPAP.