End gateway suffocation

Hey, So I've played minecraft for at least 6 years. I've been recently playing hardcore mode a good bit. I recently for the first time, beat the game (killed the ender dragon), got elytra, killed the wither, and was starting to develop my world more. I decided to travel to more end cities and went through the end gateway. After which my player started suffocating in bedrock and eventually died. This was very frustrating, seems like a bug, and has made me very angry with the game. I spent so much time on that world. I am weary of starting a new world and think you all should fix this for future players.