Also happened to me, but in a different way. I Killed dragon for first time. Used well portal, watched credits, skipping some. Was returned to the end where I used well portal again to go to overworld. Returned to the end. Built platform with water around end gateway. Swam through end gateway expecting to land on a platform. Instead, I was teleported to void where I died and lost everything. I returned to the end and tried the end gateway again. Again I ended up in void but this time I spun around as I fell and did not see any platforms anywhere at all.
Justin Keller
Also happened to me, but in a different way. I Killed dragon for first time. Used well portal, watched credits, skipping some. Was returned to the end where I used well portal again to go to overworld. Returned to the end. Built platform with water around end gateway. Swam through end gateway expecting to land on a platform. Instead, I was teleported to void where I died and lost everything. I returned to the end and tried the end gateway again. Again I ended up in void but this time I spun around as I fell and did not see any platforms anywhere at all.