Ender Crystals placed during the release of the beam after the Ender Dragon's death cannot revive the dragon

Ender Crystals placed during the release of the beam after the Ender Dragon's death cannot revive the dragon

I try to play in Creative Mode in Minecraft one day. And I give myself an Ender Crystal and the 255 level of the effect Strength for fun. I killed the Ender Dragon and try to revive it with Ender Crystals when it was releasing the beam.

What I expected to happen was...:
I can revive the Ender Dragon (when it is still releasing the beam).

What actually happened was...:
The Ender Crystals didn't work at all.

Steps to Reproduce:

1. Play in Creative Mode

1. Kill the Ender Dragon

2. Place 4 Ender Crystals in the process of reviving the ender dragon when it release the beam after the Ender Dragon dies