It's the camera control button that causes all the chaos.

The Action button replaces the small switch that used to set an iPhone to silent. That's still a job for the Action button, but that isn't all it can do.

The Action Button is a genuinely new button on the iPhone 15 Pro and iPhone 15 Pro Max but not the regular iPhone 15 and iPhone 15 Plus. Instead of the mute switch that’s been on every iPhone since ...

The Find X8 Pro’s Quick Button blends in with the smooth chassis of the phone, and I often only remember it after it grazed against my hand when I picked the X8 Pro up.