According to reports from Taiwanese website Apple Daily, a woman from Taichung City, Taiwan purchased a 64GB iPhone 8 Plus on Sept 23 and was using it for three days until the battery suddenly started swelling while the phone was charging.
According to the woman, the phone was only charging for three minutes before it started swelling up.
Photos posted by the woman show that the battery has swollen so much the display panel has separated from the body.
She had apparently been using the original charger supplied with the phone to charge it.
Another user in Japan also posted photos to Twitter of a brand new iPhone 8 Plus with the same problem.
Twitter user Magokoro0511 apparently brought the phone home, opened it up and discovered that the battery had swollen inside the phone, again causing the display to separate from the body.
The man was apparently so worried that the iPhone would explode that he put it in a frying pan and covered it while waiting for it to be picked up and returned.