Version:           git master (using Devel) 
OS:                Linux

This might be the same problem as bug 261799, but this is reproducible when using single monitor.

0. make sure all Konsole windows are closed
1. switch to an empty virtual desktop
3. launch Konsole through krunner( let's call that Konsole window as Konsole #1)
4. (optionally)change the tab title format of the only tab in Konsole #1 to "#1", so that its title bar becomes "#1" for better recognition.
5. use "File -> New Window" to get another Konsole window( call it Konsole #2)
6. launch dolphin
7. set Konsole #1 as fullscreen mode
8. use Alt+Tab to switch between Konsole #1, #2 and dolphin. No problem at the moment.
9. set Konsole #2 as fullscreen mode, too
10. use Alt+Tab to switch between Konsole #1, #2 and dolphin.


Reproducible: Always

Steps to Reproduce:
0. make sure all Konsole windows are closed
1. switch to an empty virtual desktop
3. launch Konsole through krunner( let's call that Konsole window as Konsole #1)
4. (optionally)change the tab title format of the only tab in Konsole #1 to "#1", so that its title bar becomes #1 for better recognition.
5. use "File -> New Window" to get another Konsole window( call it Konsole #2)
6. launch dolphin
7. set Konsole #1 as fullscreen mode
8. use Alt+Tab to switch between Konsole #1, #2 and dolphin. No problem at the moment.
9. set Konsole #2 as fullscreen mode, too
10. use Alt+Tab to switch between Konsole #1, #2 and dolphin.


Actual Results:  
In step 10, quite often, when I want to switch the current window from konsole #2(or #1) to dolphin, Konsole #2(or #1) is still shown in the front in fullscreen mode as if "Keep Above Others" has been enabled.


Expected Results:  
same result as in step 8


This is reproducible using a clean account, so it is not related with kwin rules

And the problem does not exist when using konsole in GNOME and XFCE

The code within Konsole directly related with fullscreen mode is only this:

void MainWindow::viewFullScreen(bool fullScreen)
{
    if (fullScreen)
        setWindowState(windowState() | Qt::WindowFullScreen);
    else
        setWindowState(windowState() & ~Qt::WindowFullScreen);
}

I failed to see how that might possibly lead to the reported problem, so I report it as a kwin bug.