The pilot's first quote is "we have an indication that is not correct in the plane" - if he felt that under no modes could the cabin altitude rise to dangerous levels, when a "Cab Press" alert came on he might have been lackadaisical about it, and simply thought the indication itself wasn't correct.

Being a brand new plane I think it had the G1000, like my plane, as the new TBMs seem to be fit with this system. Not sure how pressurization is managed through this as my plane is not pressurized - does it simply have a delta-P alert or if it displays actual cabin altitude.

I'm guessing he just got a delta-P alert, didn't realize the urgency (thought it was simply an indication not correct), and then was overcome with hypoxia. Shame he didn't wake up on the way down.