Why is my pressure increasing?

Hi all,
I have been using a CPAP for about a year now, I was diagnosed with an AHI of 17. Recently I have been having problems with my CPAP cranking up the pressure while I'm asleep and it wakes me up. Sometimes I will just turn the machine off then back on and try to get back to sleep, other times I just rip my mask of and go back to sleep. The increased pressure is extremely disruptive and uncomfortable, especially after I wake up. Why is the pressure increasing like this? and how can I stop it?

if there is actually an event then fine, but I don't think there is, and it would also be nice if it returned back down to a normal pressure much more quickly. I am considering changing my maximum pressure to something like 10 instead of 20... is this a bad idea? My 95% pressure last night (first screen shot below) was 10.9, and my week/month/6 month/year is 11.78/10.28/8.36/7.80

I should note that I've been using an AirFit f30 for most of the last year, but a couple of weeks ago I bought an AirFit f40 to try out because I needed a new cushion and figured id give the new mask a try.

These machines will increase the pressure for snores and flow limitations as well as the obstructive apneas and hyponeas.

You probably would fine limiting the max......just watch to make sure that not allowing the machine to go higher might allow some apnea events to manifest themselves. May not as well....just watch to see if anything happens.