What was expected was: The end crystals and cages respawning
What the glitch did was: Blow up the end pillars and not respawn the end crystals and sometimes destroying them seriously.
Steps to Reproduce:
1. Go to the end and kill the dragon
2. Respawn the dragon with end crystals
3. The end crystals and cages on the pillars should respawn.
4. The glitch makes the pillars blow up and get damaged instead of fixing them back.
Linked issues
Comments

Thank you for your report!
However, this issue is a Duplicate of MC-138225.
If you have additional information, please add it to that report.
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Iron Golem, the future versions will be affected if the glitch is not fixed.
I reported 2 bugs
1. End gateway teleports entities back to obsidian platform {unfixed}
2. Dragon respawning destroys obsidian pillars {unfixed}