Error at world loading : ConcurrentModificationException

[Djbapt]

Bug Description

Since this morning, when I load my world, the games crashes and exit with this error : The game crashed whilst exception ticking world Error: java.util.ConcurrentModificationException Exit code : -1 I tried shutting down the computer, uninstalling the modpack, updating it to 3.2.1 (was 3.1.7 when the bug first occured).

Did this behavior use to work in the previous version?

The bug isn't due to an update. It happened with the game in version 3.1.7.

Steps to Reproduce (for bugs)

1. Opening your World in Singleplayer screen.

Logs

• Crash Log: https://pastebin.com/ndcxJLNN

Client Information

• Modpack Version:3.1.7
• Java Version:1.8.0_202
• Launcher Used: Curseforge
• Memory Allocated: 6500Mb
• Server/LAN/Single Player: Single
• Optifine Installed: No
• Shaders Enabled: No

World Information

• Modpack Version world created in: I don't remember, I don't know where we can see that
• Additional Content Installed: None

[sam-kirby]

Have you tried restoring a backup and playing from there?

[Djbapt]

The oldest backup from the day before the problem occured still makes the game crash. The one before is one month old and isn't complete :/