Deep sleep not working

Deep sleep does not appear to be working on my MBA. If close the lid and open it in the next few minutes, it wakes from sleep normally. If I close the lid and let it sit for a while, then open it, I have to press the power button and wait for it to boot all over again.

The battery is fully charged.

Any idea what's going on?

 

Update: Apple wants me to return the unit for their engineers to look at and will replace it.