This has been a year of coin-flips. Should upside-down letters look more like the letter which they have to become, or more like the original letter only upside-down? Should a letter remain capitalised, or should it be entered in lower case to resemble a Russian letter? There have been other examples as well and it's been personally very disappointing to have made the wrong choice in every single instance this year.
Now we have the latest puzzle and I agree that the choices are much clearer this time. If you look at the instruction derived from the down clues and note the use of the word "disappearing" in the rubric, it is very clear that there should be no vestige of these thematic objects remaining in the final grid. By analogy there should only be one remaining of the other type of thematic object, even though this means you must draw a circle around its now empty starting cell and another around its final resting place.
All of this is as clear as daylight to me - clear, but I suspect not what the setter intends, for now we have a grid with a lot of spaced cells and it would be possible to have a correct grid even if the solver had not solved all the clues correctly.
Thie instructions could equally be interpreted in an entirely different way which I cannot explain further without giving the game away which is not something I'd ever want to do.
After much deliberation I have decided to submit my grid with no alterations whatsoever, bar the two encirclings demanded by the rubric. This is based more on the difficulty the setter would have had expressing the instructions unequivocally, than what has actually been written.
But, hey, it's only a guess! Given my track record this year, I would strongly advise advise anyone who is all correct so far this year not to follow my example.