[CentOS] Process owned by a user running after logout

Thu Mar 10 11:41:22 UTC 2022
Hooton, Gerard <g.hooton at ucc.ie>

After logout, process owned by the logged out user keep running.
If a user connects using ssh and then, without starting any programs,  signs out the following processes remain running

4 S Tom  1808940       1  0  80   0 - 22440 do_epo 11:08 ?        00:00:00 /usr/lib/systemd/systemd --user
5 S Tom  1808943 1808940  0  80   0 - 75441 -      11:08 ?        00:00:00 (sd-pam)
0 S Tom  1809033       1  0  80   0 - 108596 x64_sy 11:08 ?       00:00:00 gio monitor -f /run/systemd/sessions/13496
0 S Tom  1809062 1808940  0  80   0 - 16095 do_epo 11:08 ?        00:00:00 /usr/bin/dbus-daemon --session --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only

This only applies to users who use ssh, when using the system console [Gnome 3 desktop] all processes own by a user stop when that user  signs out.
I have a number of users who use the computer for remote access and the number of these running process grows over a few weeks.

I am using CentOS Stream 8.
Kernel :  4.18.0-365.el8.x86_64 #1 SMP Thu Feb 10 16:11:23 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux