Today my iPhone shut off instantly as I pressed the sleep/wake button to wake its screen; the phone was on. There was no spinning animation as it shut down. I briefly saw the screen flash to the "locked" view before it went black.
When I restarted the phone it indicated that I had 42% battery remaining.
At the time of the "crash", I was near the finish of a 2.5 mile run, and I was running a development build of iMapMyFitness. It was relatively cold outside -- probably between 30 and 40 degrees F.
I downloaded an app called System Log, and it shows the following two diagnostics with timestamps just before the crash. The next diagnostic is approximately 8 minutes later after I restarted the phone.
Message Exiting... Facility com.apple.console ASLMessageID 655 Level 5 Sender com.apple.assetsd Time 1325797737 PID 78 Message MultitouchHID(1cd0e030) uilock state: 0 -> 1 Facility kern ASLMessageID 656 Level 5 Sender SpringBoard Time 1325797751 PID 30
Is this indicative of an iOS defect, an app defect, a hardware problem, or even something else?