On the KDE task manger panel is a clock, since upgrading to 4.11.2 the clock no longer updates, or does so infrequently. I've seen it get 50 mins behind. Simply clicking on the clock (to open the calender) or typing "date" on a command line, will cause it to update to the current time. Reproducible: Sometimes Steps to Reproduce: 1. use KDE for a while 2. compare displayed time to "date" on command line 3. click on clock to see real time Actual Results: "date" on the command line is different, KDE clock time changes to that time. Expected Results: They should be the same. I could not find a specific component for the clock. I found many clock related problems but none seeming to match.
Restarted KDE and clock now working properly. I remember now that after the main upgrade I restarted KDE, but next day there were some more KDE bits upgraded (presumably bug fixes) which I did not restart for. I have had this problem before, upgrade KDE but don't restart and it seems to work but weird things happen. So my fault for not restarting KDE, sorry about that.