I then disabled and stopped the upower daemon but the issue remains with the only common factors being systemd-logind and lightdm.
I tried console-only tests with lightdm stopped and CANNOT reproduce the issue.
I installed sddm and changed the default display manager to use it:
apt install --no-install-recommends sddm
Tested with logind + sddm and CANNOT reproduce the issue.
Re-enabled upower via the x-p-m applet.
Tested with logind + sddm + upower/x-p-m and CANNOT reproduce the issue.
Tested with logind + sddm + upower/x-p-m + light-locker and CANOT reproduce the issue (note: light-locker dies at some point so no password dialog on resume).
Based on all this it seems to point the finger at ---> lightdm
maxpus=1 still suffers the same issue.
I then disabled and stopped the upower daemon but the issue remains with the only common factors being systemd-logind and lightdm.
I tried console-only tests with lightdm stopped and CANNOT reproduce the issue.
I installed sddm and changed the default display manager to use it:
apt install --no-install- recommends sddm
Tested with logind + sddm and CANNOT reproduce the issue.
Re-enabled upower via the x-p-m applet.
Tested with logind + sddm + upower/x-p-m and CANNOT reproduce the issue.
Tested with logind + sddm + upower/x-p-m + light-locker and CANOT reproduce the issue (note: light-locker dies at some point so no password dialog on resume).
Based on all this it seems to point the finger at ---> lightdm