KDE's save-and-restore-session feature gets confused by applications that are already running when KDE is started, and starts up a new instances of those applications.  Each time KDE is closed and restarted, it will start an additional instance.

Reproducible: Always

Steps to Reproduce:
1. Start with a new user account
2. Log into a plain xterm session
3. Run startkde
4. Exit KDE
5. Exit the xterm
6. Log into a plain xterm session again
7. Run startkde

Actual Results:  
KDE starts a second xterm in spite of the fact that only one was running in the previous session.  If I then log out and repeat the exercise by logging in a third time, KDE will start not only the second xterm but a third one as well.

Expected Results:  
Only one xterm was running the first time I logged into KDE, and only one xterm was running when I logged out.  When I log in again, only one xterm should be running, not two.

Arch Linux package versions:
kwin 5.1.0.1-2
plasma-desktop 5.1.0.1-2
plasma-framework 5.3.1-1
xf86-video-intel 2.99.916-3
xterm 312-1

P.S.  Your bug tracker does not handle copy-and-paste well.  Each time I copy this list of package versions from a previous report, it all gets merged into one line and I have to add the line breaks again manually.