"I got it from REI pre-warranty change, so I may just return it."
I just returned an air mat with a blown baffle to REI that is about 3 years old. The CS rep said
1) it is "grandfathered in" as it was purchased before the change,
2) "manufacturer defects" are covered "indefinitely",
and "not to worry".
We'll see how it goes when the rubber hits the road.