Hello. Has anyone else encountered an issue where they are using their Mid-2013 MacBook Air (13in) on battery when the machine suddenly goes to sleep or appears to, but it has actually crashed. The screen is dark, keyboard and trackpad are not responsive and the keyboard backlight is on. You have to force it off to restart by pressing and holding the power button? It is completely random, not a kernel panic, and nothing I can see in any logs. After the recent firmware update the symptoms changed such that the display is still active since the Apple logo is lighted. I've never had it happen when I'm on a/c power. Unfortunately its random and infrequent too. The recent firmware indicated it helped with battery issues, etc. didn't fix mine apparently.