How the Aircurve 11 vauto works

hi all, quick question

as i am working thru the "getting used to cpap" stage, ive noticed something in my SleepHQ and OSCAR data that has me confused.

1st, bpap, 23/19 ps 4. got the mask leak issues under control. i have a mix of OAs and CAs with a majority of days the CAs are >50% of the events.

when i zoom in on the breathing chart i see the OA & CA events. i noticed that my pressure drops to 19 (sometimes a bit lower).

should the machine be raising the pressure to counteract the event? seems like its doing the opposite.

thanks in advance!!!!