What I am not sure about is how the machine treats hypopnea during large leaks. It does have the ability to classify apnea events as unidentified apnea or UA. I have seen those. They are apnea events, but the machine just cannot determine what type they are, obstructive or central.
My wife had a bad night for leaks a couple of nights ago and even got the red unhappy face on the sleep report. That takes a lot to bring that up. Here is what it looked like. As you can see AHI was still very good, and no events flagged during or after the largest leak period.
And the other thing you can do if you think the machine is not reporting events properly is zoom in and look for apnea events where there is no flow. I did that for this large leak period and only found one potential apnea event and zoomed further in on it. See this graphic. The event starts where the green vertical cursor line is and continue on for near 10 seconds. After 4 second the machine starts to oscillate the flow to test for the apnea type. You can see that as the high frequency cycle in the mask pressure, starting at 4 seconds. However it does not flag it as an apnea event. I would have expected to see it flagged as a UA. I'm thinking it ended just short of the 10 second length required before it is classified as an apnea event.
In any case you can see how to manually check for events during a high leak period manually and decide if there are missed events or not, Hypopnea is harder as I have trouble seeing what the machine classes as hypopnea. But, you could use a similar process to look for them. Find a hypopnea event that is flagged as such, zoom in and see what it looks like, and then search for that pattern during your high leak rate periods to manually look for them.
If you think your machine is not responding properly to events due to high leakage you can always switch to fixed pressure CPAP mode. That is how my and my wife's machines are set. Unless the leak is super huge, like the mask falling right away from the face, the pressure is maintained right through the high leak periods. The standard way of switching to a fixed pressure is to look at the statistics page and find your long term average of the 95% pressure and then just set the fixed pressure at that value.
Hope that helps some,