In my server, every ender crystal in end generate 1 "#fire placed fire" event per tick, after 2 month of running, database is filled with ~ 30GB such events.

Unable to replicate.

The fire normally doesn't go out, and isn't placed multiple times. Something else on your server may be modifying fire behaviour.

This is the ender crystal entity that heals ender dragon, not player placed blocks.
The dragon is killed, player pushed the crystal away by pistons out and keep them as Tutorials/Indestructible end crystals.

In my server, every ender crystal in end
This is the ender crystal entity that heals ender dragon, not player placed blocks.

Yes, I tested in the end, no issue.

Please test without any other plugins and let me know if the issue persists.

I can replicate the issue:

1. start a new server (latest Paperclip-235, latest coreprotect, no other plugins, all settings/configs default)
2. Enter server, goto end (/setblock ~ ~ ~ end_portal ) , kill dragon (/kill @e[type=ender_dragon])
3. stop server and copy .mca to world_the_end/DIM1/entities
4. restart server, issue replicated.
   r.0.0.zip
   

That appears to be just from exploited end crystals floating in the air, which causes the BlockIgniteEvent to be spammed. (Not a CoreProtect bug)

However, I'll add a patch to prevent unnecessary data from being logged.

Fix will be included in CoreProtect v21.1.