I was making a redstone machine and I tested it and I got the mysterious ghost block that happens on servers but it was singleplayer. You can recreate it by loading 20w08b and making a singleplayer. Follow my video and build it exactly how I build it and step where I step (sorry for video quality, had to lower dimensions because of the file size limit, higher quality here https://www.mediafire.com/file/6i1rnrs1znozusu/2021-03-09+19-06-11.mp4/file)