I was just coming back from getting sulker shells from my shulker farm. I was going to go back through the main gate but decided to go through one that was closer. I preceded to fly through the end gateway and got put in the void. Also just in case you needed to know, this was on a realms server.

I did not record it happening, nor have I yet been able to recreate this issue. I will add to this if I'm able to recreate it.

edit I think I understand What might have happened though, I believe that the game might have kept me in flight mode and sent me straight into darkness where I preceded to die. Maybe something along the lines of what I just now added except I was sent way deeper into the void.