Is it starting up, asking for the pin and shuting down after about a minute?
If yes, I had a similar problem this week which was likely caused by an app. I booted into safe mode (on my S7 it’s holding Vol- during boot) and the problem vanished after I uninstalled some apps (VLC, Firefox Lockwise and Shield Experience). Didn’t invest the time yet to check which app caused it. It even happened in safe mode.
Interesting, yes once the cycle starts it gets to pin request. I can not get past that before it reboots. Will delete apps and see. FWIW I do not have those apps installed that you mentioned.