SUMMARY
If a parent application opens a child window on another workspace, panel set to "Windows can cover" forces to remain on top as long as you don't focus on the child window.

STEPS TO REPRODUCE
1. Set your panel to "Windows can cover" mode
2. Create at least 2 virtual desktops (workspaces)
3. In a workspace #1 open your default Internet browser (required step!)
4. In a workspace #2 open any GTK application (aka. Telegram) that could display any clickable URL and make sure that its window almost touches the edge of the screen closest to where your panel (configured in step 1) is placed
5. Inside of your GTK application (aka. Telegram) open any URL by clicking on it
6. Check the weird behavior of your panel (configured in step 1) that pops out at the top (your GTK application window will not cover the panel unless you visit workspace #1 and make a focus on your browser window first)

OBSERVED RESULT
When you click any URL in step 5, your panel goes on top of all windows in worspace #2. Clicking any window will not bring it up above the panel. You have to open workspace #1 and click your default browser to get its focus and then you can go back to workspace #2 in order to see the panel is not forcing its focus on top anymore.

EXPECTED RESULT
After step 5 above, the panel should not force to become on top if the target activity/window is on the other workspace.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Manjaro KDE Plasma
(available in About System)
KDE Plasma Version: 5.20.4
KDE Frameworks Version: 5.76.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION