In Java edition the entity goes in the end gateway it spawn on the cordinate 0,0 at the surface of the overwold but on bedrock it summons them on 0,0 but 32000 blocks high.Sometimes the dragon egg fall into the end gateway and cause it to fall from such a high taking upto 10min to reach ground but it despawns at 6min,this is a problem since the dragon egg is only obtaineble once in the game.