It’s common for some newly released smartphones to experience problems. Huge production numbers and the rush to get the handsets ready in time often mean issues do appear — some more serious than others. But as Samsung would tell you, anything relating to the battery can be worrisome. Sadly for Apple, the iPhone 8's battery could be why some of the handsets are reportedly bursting open.

Photos have appeared on Twitter from iPhone 8 Plus owners showing the handsets with massive splits along the sides. Some say the casings cracked as they were charging the phones using official accessories, while others claim the devices were already destroyed when they opened the box.

Just how many iPhone 8 buyers have experienced the problem is still unknown, though it appears to be several isolated cases rather than a more widespread issue. According to The Independent, Apple believes the splitting is caused by battery swelling but says it does not pose a safety concern. The company confirmed it is “looking into” two reports of the issue.

Even if this is just a few rare instances, it’s more bad news for the iPhone 8. The handsets come with few upgrades over their predecessors, and most Apple fans have shunned them in favor of the iPhone X, which launches in November. The muted interest in Apple’s latest handset led to some of the smallest lines for a new iPhone in years.

Last week, Apple confirmed that some iPhone 8 owners are experiencing a crackling or static sound that affects the handsets’ audio, but said it is working on a fix for the problem.