I have discovered that leaving Windows 10 firewall active while Norton Security Firewall is active will cause most apps to create a system shutdown. Once I turned Win 10 firewall off (Norton Security firewall still ON) that after several times of starting an app with shutdown problems, the problem went away. Microsoft Edge would cause shutdowns (but not now), Word would do the same, several games also.
I could not find where Norton Security automatically disables Windows Firewall. I believe that Norton Internet Security did that.
It's been fun trying to find what was going on. Event Viewer was never handed an event to record the shutdown.