SUMMARY

After waking up from screen saver, panels on second screen go all wonky. Either disappear, or an included task manager shows up tasks from the wrong screen. Restarting plasmashell then "fixes" it

STEPS TO REPRODUCE
1. On second screen, set up a panel with a task manager with "Show only tasks from the current screen" is ticked.
2. At first, it does indeed only show tasks from the second screen, as it should
3. Wait 10 minutes for the screen saver to kick in
4. Move the mouse to wake it from screen.
5. Now, the task manager in the panel on the second screen shows tasks from the *first* screen. Sometimes, that panel is also gone altogether (i.e. not displayed at all)
6. Execute kquitapp plasmashell ; nohup plasmashell >/dev/null 2>&1 </dev/null &
7. Now, everything is back to normal

OBSERVED RESULT

After wakeup, task manager in the panel on the second screen shows tasks from the *first* screen. Sometimes, that panel is also gone altogether (i.e. not displayed at all). Things get back to normal only after restarting plasmashell

EXPECTED RESULT

The task manager should display the tasks from the screen it is on, and not from some other screen

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Where is "About System"? (Full path...)
(available in About System)
KDE Plasma Version: 4:5.14.5.1-1
KDE Frameworks Version: what is the name of the package?
Qt Version: 5.11.3+dfsg1-1+deb10u3

ADDITIONAL INFORMATION