Bug 512487

SUMMARY
Icons-and-Text task manager loses open windows when second display is disconnected and "Show only tasks: From current screen" is enabled.

STEPS TO REPRODUCE
2 display configuration (secondary display left-of primary) on Wayland with AMDGPU drivers.
1. Configure Icons-and-Text task manager on each screen's panel with "Show only tasks: From current screen" checked.
2. Work for several days in a single KDE session (with suspends but w/o logout/shutdown)
3. Physically disconnect the second (left) screen

OBSERVED RESULT
There are no more tasks for open windows/applications on the Icons-and-Text task manager

EXPECTED RESULT
All opened windows/applications should have an item on the Icons-and-Text task manager

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.2

ADDITIONAL INFORMATION
Wayland, 2 displays:
Left: Secondary, HDMI, 1440p
Right: Primary, DisplayPort, 1440p
AMDGPU open-source stock drivers
Ubuntu 25.10 amd64

I have Icons-and-Text task manager on both displays configured to show only tasks "From current screen && From current desktop && From current activity" (I don't use activities)

Sometimes when I disconnect the second display all the tasks disappear from the main screen's  Icons-and-Text task manager (so it becomes empty and display no more tasks). The only way to see them back is to uncheck "From the current screen" checkbox.
This happens not always, but after several days of working. My current uptime is 27 days.