Leak event flags vs. Leak rate graph

[verysincere]

I have a basic question about understanding the correlation between what I see in the leak rate graph versus the LL (I assume that means Large Leak) event flags in the event summary map graph. 

For example, in the attached graph, around 1:50am, it shows a significant, though relatively brief, leak---but there is not an LL event flag.  Was the duration too short to qualify as a large leak---or is its leak rate of 36 too small to qualify as a LL?  (Indeed, what defines a Large Leak, if that is what it means?)

Also, how does Resmed DEFINE the leak rate? I read somewhere that some manufacturers include the "baseline leak" of the machine in their leak rate quantifier number but others quantify the EXCESS leak over the base rate. Do I understand this correctly? (Of course, because I have a Resmed machine, I'm most interested in what their leak rate numbers indicate.)

Thanks for your help. I've lowered my AHI significantly with the help of this board.

[Crimson Nape]

All masks have a designed or intentional leak.  The Philips brand of CPAPs will report the intentional leak and any leak above its designed value.  The Resmed CPAPs only report any leak above the designed value.  Resmed defines a Large Leak as being over 24 L/min. The reason your leak wasn't flagged was probably because it didn't last long enough.  This could be from a quick mask adjustment or even scratching your face under the mask.  Your leak blip is referred to as an artifact within the data.  Artifacts occur in most data streams.