404 Media reported that iPhones stored by police in evidence were rebooting themselves, and it turns out it’s all due to a new Inactivity Reboot feature shipping in iOS 18.1. First reported by security researcher Jiska Classen, this new feature reboots your iPhone if it has gone unused for at least four days.

Apple's iOS 18.1 auto-reboot feature locks iPhones after four days, blocking easy access, but at the same time, frustrating law enforcement in forensic probes.

A hidden feature in iOS 18.1 will automatically reboot a locked iPhone when it is asleep but hasn't been unlocked for a while, presumably as a security measure.