Three ender dragons

When I reached the world of the End, I came across the dragon, but when I destroyed two towers of life he killed me by throwing me off the map, of course, I lost all my weapons and armor, my surprise was that when I returned there was no one, if not three dragons of the End, then I tried to lower the difficulty to pacific and even so they disappeared, restart the game, the console and nothing, I even made the achievement "You need a mint" in which you have to collect dragon breath in a bottle of glass and they did not give it to me, they have already spent days and I do not manage to solve it, please, solution in which it is impossible to take out the achievements of the End with three dragons hanging around.