I haven't seen those rumors myself and have no reason to think there is any validity to them. As the saying goes, there is nothing new under the sun. Story ideas are going to reappear from time to time, with no intent to copy another's ideas and work.

There is a short story around the scifi circles that Mrs. R. A. Heinlein appeared before a Senate subcommittee looking at a proposed rule change extending the copyright period. She spoke against it, pointing out that it would kill the chances for new authors, by building a wall around all the existing ideas. Eventually all possible ideas would have been used. She said the current copyrights gave plenty of time for existing authors and their families to monetize the work, that ideas need to be freely exchanged.