Had the same issue a month ago and (prior to reading this thread) went through all the steps and still no fix. The only way I was able to prevent it was by using that ugly multicolor screensaver. That worked for about a month.
This weekend I needed to use the power saver option to keep my battery life while traveling. When I switched back to optimized, the lock screen reboot/power down came back.
this must have triggered something in the security and battery saving settings. Because turning off the fingerprint scanner definitely worked but I also noticed a lot of my settings for both security and battery did not return after the battery save switch.
definitely frustrating. And nobody wants to go through the trouble of constantly getting new phones. Samsung needs to figure this out fast. This phone wasn't cheap and they had enough time to fix the initial bugs
... View more