Sorry, the snip from the second screenshot was pasted the whole width, I will attach them as 2 separate screenshots, instead of an edited one. If you edit these together to compare them, you should see that everything else matches up but the doors.
This was the first dragon, that spawns in when first loading the End.
The dragon XP was split over a few players, but I have confirmation that one of them was around level 40 after the fight.
I can no confirm that it is in fact somehow the tv turning off and coming back on. Not sure what is causing it but im not sure if it is really considered a bug, but thanks anyways!
The only thing that could possibly be considered as changing is me turning the tv off (i use it as audio and video), so tonight i will leave it on to double check 🙂
I have attached a recording of the pixels moving while the door is changing states for better clarification. After a second in the video, i move my cursor onto the line where the pixels are moving.