Comment # 8 on bug 959849 from Wolfgang Bauer

(In reply to Mark Fairbairn from comment #7)
> I do still occasionally see it

Hm.
I still haven't seen that a single time.

> but mostly after a plasma freeze and the need
> for a hard reboot(running intel graphics) - but dolphin opening up here is
> probably unrelated (although it does tend to open up even if there were no
> instances of dolphin open at the time of the freeze).

Well, if you do a hard reboot, the previous session is being restored, as the
session is of course only stored on logout.
But then, you already should have had dolphin being restored in the current
login...

If it happens the next time, could you maybe tell the exact command line with
which dolphin is being started?
To get that, hover over the dolphin process(es) in ksysguard (Ctrl+ESC), or run
"ps ux|grep dolphin".

Should give a clue whether it's being restarted by the session manager or not,
and might even hint at the problem in any case.

In this case (hard reboot after a freeze) it could also be caused by some
filesystem inconsistency I suppose, but I think that's hardly a reason why
(only) dolphin should be restarted.
Still, also try to delete ~/.config/ksmserverrc, and see if that "fixes" your
problem.