Ok, some added details on my "rebooting" although it doesn't show the samsung logo, so I don't think it is a full reboot.
I have noticed that the only time it happens is when I lock the screen or when it locks itself. Sometimes it has been locked for a while and it will randomly do it. I don't believe it has ever happened while I was using it. Oh, and a few times it happened while unlocking the screen. So it all seems to be related to the lock screen. I don't have any apps that add functionality to the lock screen. I have a pattern unlock and Smart Stay enabled (although this never worked for me, maybe my face is too weird to be detected? Lol). I am going through the process of turning off things to see what might be causing the problem. The first thing I disabled was the LastPass accessibility extension. I will give it a day or 2 but I have been playing around with locking and unlocking with various apps open as i write this and I haven't had a "reboot" yet.
I noticed that another poster had trouble with a different app and like him this trouble started after I rooted it. The LastPass accessibility extension worked fine before rooting. I will tell you what this extension does and maybe it will help us narrow down what area of the system has been changed to be incompatible with certain software.
The extension "watches" for password entries on apps and webforms and offers to autofill with saved passwords.
Sorry for the long post, hope it is helpful to someone.