Bug Report

[Failed to load save.
java.lang.IndexOutOfBoundsException: Index: 1, Size: 1]

What's the issue you encountered?

tried to load a save file and got the bug metnioned above
[ Describe the issue in detail and what you were doing beforehand. ]

How can the issue be reproduced?

im not sure how to reproduce this

Logs

https://gist.github.com/SDUBZ/ce6a918a38648c4d07d498611d47fc19

Mod Version

BiomesOPlenty-1.16.3-12.0.0.405-universal
Forge:1.16.3-34.1.16

Got the same problem and managed to find the cause (in my case at least): woot-1.16.2-1.0.0.0
A world created with woot & BOP, will trigger this error when trying to load the world.

Since Woot is not updated to 1.16.3, this is most likely the reason.