When you kill an Ender Dragon for the first time, it spawns an Dragon Egg on the pedestal, which can be collected, since the dragon can be revived without the Dragon egg. This works as intended. The issue is... If the egg is not collected from the pedestal, and you try revive Ender Dragon with an Egg still on top of the pedestal, the Dragon Egg dissapears forever.
How to reproduce:
Create New world
Enter The End and Kill Ender Dragon
Collect Dragon Egg
Craft Ender Crystals and revive Ender dragon
Result: You still have an Egg when the Dragon is revived
And then:
Kill ender dragon
Place Dragon egg back at the pedestal
Revive Ender Dragon
Result: You lose Dragon Egg forever
I thought the egg was needed to respawn the dragon so ain’t this perfect