The process for the desktop protocol died unexpectedly

Since installing Leap 15.2 with KDE, I the above message is frequently displayed on the desktop.
This was a clean install, retaining the Home partition and the message didn’t appear on first start-up using the software graphics drivers (a huge improvement on the old arrangement by the way). I then installed the latest Nvidia drivers and subsequently the message appeared (there may be no connection though - the message isn’t always there).
Logging out and -in makes no difference.
I haven’t encountered any further problems, and hence can live with it, but it is slightly irritating, and I would like to know what’s going on.
The only vaguely relevant information that I could find was old, e.g.
and didn’t really seem to describe the same issue.

I’ve had the same problem with 15.2 (and possibly 15.1, I forget, it’s been happening for so long). Happens maybe 60-70% of the time when I login and (I think) also when coming back from sleep.

I also have NVIDIA drivers FWIW. Been the same through many NVIDIA driver updates though. I’ve played around with the compositor setting, but doesn’t seem to make a difference.

I don’t really have any idea where to start looking for a solution…