Whilst fighting the ender dragon, I noticed you take no damage whilst standing in the dragon fire from the fireballs.
I found this out by standing in dragon fire after it is spawned by the dragon fireball, you can reproduce this by doing the same.
It is supposed to damage you, but it doesn’t because of what seems to be a bug.
something I also noticed is the dragon can’t seem to damage you at all, normally it would damage you when it flies into you, but the dragon seems incapable of dealing any damage.