I've had this fresh install for a few weeks and it has only happened once. But earlier year with Kuvuntu 15.04 it happened multiple times. Reproducible: Sometimes Actual Results: Desktop crashed. It came right back up spontaneously. But I had to rearrange icons on the task bar. Expected Results: Cleared clipboard.
Created attachment 99188 [details] results of your bug system
I've had this fresh install of Kubuntu 16.04 for only a few weeks.
*** This bug has been marked as a duplicate of bug 346740 ***