It appears that Apple may have a manufacturing problem on its hands with the iPhone 8. Two and possibly three separate events seem to have appeared in which the iPhone 8 Plus’s display has popped up from its sides.
Several things could be happening with the devices that’ve appeared with dislodged display panels. It’s generally rumoured that these devices have suffered from sort of battery related issue, one in which the battery expands, punching the front panel out from the rest of the device’s body.
One of the two clearly differentiated devices comes from Japan. Twitter user @Magokoro0511 suggests that his iPhone 8 Plus was “already swollen” when he opened the box. This would indicate that there’d more likely be a manufacturing issue than anything related to in-progress charging.
— ???? (@Magokoro0511) September 24, 2017
In at least one of the images, it’s quite plain to see that the battery is the reason for the front of the device’s movement upward and away from the back.
Apple is currently investigating the iPhones 8 in question. In the meantime, iMore suggests that you use the Apple-supplied power adapter and cable to charge your device. If you suspect that your battery is defective, turn off your device and take it into an Apple Store or call AppleCare.