Several threads on the Apple Support Communities forum are reporting random reboots on the iPhone 5s while using Apple's iWork apps, with the issue being signaled by the brief appearance of an all-blue screen naturally being compared to the famous Windows "Blue Screen of Death" (BSOD). The issue was reported by iPhone in Canada last month but has been gaining significantly more attention today after being picked up by The Verge.
As shown in videos posted by users, the issue may appear when a user simply opens a document in Pages or another iWork app and then closes the app by pressing the home button on their device. Double-pressing the home button to enter multitasking mode can also trigger the issue. Users in the threads are also reporting random reboots during regular device use, which also may be caused by a number of reasons specific to the device.
Users have reported that the error can be temporarily fixed by turning off iCloud syncing for Apple's Pages, Keynote and Numbers apps, but that fix does not appear to address the other random reboots on the device. Apple released iOS 7.0.2 last month with a fix for a lock screen passcode bypass issue, and was said to be seeding iOS 7.0.3 internally as of last week, but it is unknown if it will contain a fix, or whether Apple will deploy updates to its iWork suite of applications to remedy the problem.
Earlier today, a study showed that apps running on the iPhone 5s are crashing twice as frequently as on the iPhone 5c and iPhone 5, with the new 64-bit A7 chip and M7 motion coprocessor presumably adding wrinkles that may be causing some apps difficulties.