A small section of the previous image, showing more clearly the effects of the "white orb syndrome".
The image also shows some noise - it was taken at 500 ISO. (Set for an earlier low-light shot, and forgot to reset it!)
I also examined the RAW file which was additionally saved and the white orbs were similarly present,
suggesting that this is probably a hardware phenomenon and not a software one, and that it is
probably unlikely to be eliminated by any firmware update.
But I might be wrong, of course. I often am!
Incidentally, the noise in the RAW image could be reduced considerably by judicious adjustment in
Adobe Camera Raw. I didn't do that with this image, leaving it largely as it came out of the camera.