Something tells me it was a half-assed explanation for Palpatine’s survival that they threw in there at the last second (thus why it is never mentioned again really). Then again, there are a lot of those in this movie.
Later when writing the canon material around the movie they realized it was better to go in the cloning/transfer direction. But it was already too late obviously to change stuff in the film.
Man, sometimes I wish this movie got delayed.