@polishcolonel, There can be many causes for a sudden increase in AHI events. I don't think it's unusual for this to happen as myself and I'm sure others have had similar experiences. You might want to scan through the following discussion to learn what others have shared..

-- How to reduce my events while using my Cpap: https://connect.mayoclinic.org/discussion/how-to-reduce-my-events-while-using-my-cpap/

I haven't been using a CPAP as long as you have but have been using one for 5 years or so. Did the events just increase overnight or a short period of time?