Earlier this year I got an Alpkit Numo in an effort to hopefully reduce pack size that I had yet to try, so out it came.
2 hours in I was absolutely boiling in my new bag and venting, and the mat under me felt quite warm too, all was good.
Twice that night I woke up to find the mat had deflated enough to leave me heels and hips on the floor and getting cold, I reinflated and fell back asleep only to wake to the same thing

Am I doing something wrong? Is this a limitation of (non insulated) air mats? Or have I got a dud?
Meanwhile she slept soundly on her bulkier self inflating mat, but I planned to buy a second Numo for her but after this I'm a little stuck