You do realise don't you that when you do a factory reset, the phone still keeps the latest UI update. So your comment about auto updating later on doesn't make sense. You say it keeps restarting in safe mode, so that would rule out any rogue 3rd party apps, etc. You've also done a partition wipe, which hasn't resolved the issue.
So, after you reset the phone, did you install any backups? If so It's possible these didn't transfer correctly, and that's what's causing your issue. If I were you, I'd try a factory reset again, but don't load any backups. Don't install any 3rd party apps or customisations, and just leave the phone as is. Monitor it for 24 hours and see what happens. If the device remains stable after that, then you can start adding apps as you see fit. If not, then log it with Samsung.
