Law enforcement believe the activity, which makes it harder to then unlock the phones, may be due to a potential update in iOS 18 which tells nearby iPhones to reboot if they have not been in contact with a cellular network for some time, according to a document obtained by 404 Media.
As long as you dont turn that feature off it does. You can set it to restart if the device hasn’t been unlocked for between 10 mins and 3 days.