Plasma freeze upon resume from hibernate

Hi. Please could I get some help troubleshooting why resume from hibernate isn’t working successfully on my HP Prodesk Desktop, running Leap 15.4. The system seems to go into hibernate OK, but when it resumes, Plasma is inactive (though I can move the mouse cursor). I can get to a terminal shell, login and pkill plasma_session to force plasma to restart. What could be some next steps to investigate the problem?
(If it helps, I had hibernate working on this machine running 15.1, but after online system upgrades [not full reinstalls] to 15.2 and 15.3 it stopped working. I did a full system reinstall to 15.4 hoping the issue would be resolved, but it hasn’t…)

Something to try - Create a new user and test hibernation and resuming via that user. Any difference?