When I entered the end I was on a platform away from the main area itself. I built a bridge over to the land and noticed that I dragon was 'stuck' to the ground. I thought no worries it will move soon and proceeded to destroy the towers with my friend I was playing with. After doing so We go down onto the ground and I attempted to hit/kill the dragon. It took one 'hit' of damage then it was like it was immune to anything whilst staying 'stuck' in the ground. My friend then noticed that the exit portal was lit up while the dragon was still alive. I have attacted a short video to show what I mean.

After leaving the end and returning, hoping that it would fix itself, the dragon has dissapeared, there is no end city portal and I do not have an egg to try and respawn it.