I am trying to hit Ender Dragon with my enchanted sword and it does no damage.. Yes, all of the Ender Crystals have been destroyed. The enchantments on sword are: Sharpness IV, Fire Aspect II, Knockback II.... Never had this issue prior to TU14, although prior to TU14, I had only ever attacked ED with a Sharpness/Looting sword... I am able to make a small damage to the dragon with an unenchanted bow, however this is not an option for killing dragon as it will take forever. Does ED become invulnerable when you attack with a Fire Aspect and/or Knockback enchanted sword?
I haven't touched her in TU14, so I can't say what's what about the case.
It very well may be a bug.
Stay fluffy~