On my singleplayer survival world, I killed the ender dragon, and got the dragon egg. It is placed in a glass case in my base. However when I went to kill the ender dragon for a second time (respawn with ender crystals, etc.), and killed it, a second dragon egg spawned. I am not sure the extent of how many dragon eggs can be obtained with this bug, however obviously there should only be one dragon egg per world. I am not sure if this has something to do with the fact that the second time I defeated the dragon I was on a world copy (my original world save in which I killed the dragon the first time got corrupted) however I have seen other threads on reddit where the dragon egg spawned for a second time on an original world save, concluding that this could be a bug. This small glitch is quite game breaking so please get it fixed. Thanks!