Hello,
Did you change anything in sshd_config ?
If you can, check if you can correlate the pty/tX session with any world ID with this command :
grep -i pty /var/log/auth.log
it will raise a results like :
2018-10-10T08:44:20Z sshd[2989715]: Session opened for 'root' on /dev/char/pty/t0
where 2989715 is the current world id of the session pty/t0
Then if you retrieves all the World ID, then we can check from where it comes.
PS : Can you put your shell.log and auth.log as an attached files (or private message if you want), i'll check it out.
Let me know