My MacBook Pro is randomly returning to login screen.

My late 2013 15” MacBook Pro Retina Display running Mojave recently started abruptly returning to the login screen. ( the mac does nto restart, it reurns to the login screen).

So far, I am able to duplicate 100% when I:

1.) select or drag the mouse pointer over a file(s) in a folder or on the desktop

2.) taking a screen shot after pressing cmd-$@$*-4 on laptop and bluetooth keyboard

3.) creating a new tab in Safari via the file menu or clicking the “+” symbol ( does nto happen using Chrome and Firefox)

I ran the MAC OS diagnostic tool, it did not reveal any issues other than internal battery would need replacement soon.

Safe Mode: This issues do not happen in Safe Mode. There is no returning to login screen

Since this recently started happening, I’m wondering if it might be a corrupted font or a third-part tool/app somewhere in my user/library folder?

Is there a tool/application that would help me isolate the culprit?