Some reports take note that iPhone 6s and 6s Plus users has been experiencing a bug that unexpectedly shuts down the device. Apple is yet to address and make a statement about the said issue.
iPhone 6s and iPhone 6s Plus users have been complaining on Apple's discussion page about the automatic shutdown they have been experiencing. Complaints started back in Sept. 25, wherein others reported that their devices began to heat up before shutting down, and had a hard time bring it back to life.
In a report by MacRumors, other than the random shutdown the users have been experiencing, another bug may have been annoying users as some reports suggest that their displays were not as they usually were. The displayed seemed to be zoomed in and cuts of the edge of the screens, thus making some of the features unavailable to view.
These bugs somehow began to appear when users updated their phones to iOS 9. This bug seems to be affecting other models as well including iPhone 5, 5s, and 5c. The bug seems to affecting the Apple apps such as the Weather, Watch Calculator, Health, and Wallet as well.
A temporary solution for the zoomed display was then posted. The zoom can temporarily be fixed by tapping the Zoom in the Accessibility Settings, which will enable the zoom feature. Another kind of fix is manually setting up the iPhone as a new device.
As for the automatic shutdown but, in a report by ZDNet, they suggested that the problem can be solved by resetting the phone back to its factory version. ZDNet even added that Apple will be releasing a fix for the "Zoomed-in" bug for the iOS 9.1 update though there aren't any announcements regarding a fix for the "shutdown" bug. For now, users may settle by resetting their iPhones to fix the "shutdown" bug while waiting for an official fix from Apple.