Ender dragon revival sequence places end crystals on top of the pillars even if they already have an end crystal

I can confirm this issue though idk it's intended or not. I also wrote a better "Step to reproduce":

Steps to Reproduce:

Step 1: Use /kill @e[type=minecraft:ender_dragon] kill the ender dragon.
Step 2: Break all end crystals except for one.
Step 3: Look at that end crystal, use "/data" command to make that end crystal glows:

/data merge entity <ID-of-that-end-crystal> {Glowing:1b}

Then press Enter.

Step 4: Revive the ender dragon.
Step 5: Watch carefully to see that end crystal is now glow or not.

Observed Results:
The end crystal don't glow.

Expected Results:
The end crystal still glow.

Screenshots:

I don't think that glowing is the issue reported here, I'm inclined to think that the issue is the respawning sequence placing an end crystal atop a pillar that already has a crystal.

Affects 1.21.4. Looking to request ownership of this report to maintain it.