Video from iPhonedo showed an iPhone 15 Pro Max hitting 96 degrees after the Instagram app was opened
While iPhone units can get hot when the processor is doing some heavy lifting, like when the user is playing a graphics-intensive video game, for example, the current issue goes well beyond those situations and some have used digital thermometers and ultraviolet imaging to determine that some iPhone 15 models are hitting temperatures in the triple digits (Fahrenheit).
Since Apple released iOS 17 on September 18th, it has already released iOS 17.0.1 to patch two security flaws, and iOS 17.0.2 was released to exterminate a bug that was freezing iPhone 15 models in the process of transferring data from an older iPhone unit.