Some of the first owners of Apple Inc.’s iPhone 15 Pro and Pro Max are complaining that the new devices get too hot during use or while charging, a potential setback for the company’s flagship product.

The gripes have spread across Apple online forums and social media networks, including Reddit and X. Customers say that the back or side of the phone becomes hot to the touch while gaming or when conducting a phone call or FaceTime video chat. For some users, the issue is more prominent while the device is plugged in to charge.

Apple technical support staffers have been fielding calls about the issue as well. They’ve referred customers to an old support article on how to handle an iPhone that feels too hot or cold. The notice says overheating could occur when using intensive apps, charging or setting up a new device for the first time.

A representative for Cupertino, California-based Apple didn’t respond to a request for comment.

The iPhone accounts for about half of Apple’s revenue, and new models are closely scrutinized for any potential flaws. Sometimes problems crop up that have to be addressed by Apple – with software updates or other fixes – but often the concerns fade on their own.

Apple also has a rigorous testing process in place that’s meant to catch any pitfalls before the iPhone goes into mass production.

Having devices get warm is not an unusual phenomenon, especially given the supercharged processors that power modern gadgets. The question this time is whether the heat problem persists and goes beyond what consumers think is acceptable.