Server Crash When Generating New Terrain

The server crashed when trying to generate new chunks. The crash occurred specifically when the game was trying to place mangrove trees in new terrain, probably caused by Mob Grinding Utils's Delightful dirt updates.

When Does It Happen

When exploring to new areas that haven't been generated yet
Specifically when mangrove trees are being placed during world generation (beside delightful dirt?)
I am playing on FTB Skies 2 which has some structure that meets both conditions : Mongrove + Delightful. It might not be a mangrove issue, it just mentionned in the crash log as is. That issue has also been reported on FTB Skies 2 issue tracker

Error message

Caused by: java.lang.ClassCastException: class net.minecraft.server.level.WorldGenRegion cannot be cast to class net.minecraft.world.level.Level (net.minecraft.server.level.WorldGenRegion and net.minecraft.world.level.Level are in module [email protected] of loader 'TRANSFORMER' @e36bc01)
	at TRANSFORMER/[email protected]+mc1.21.1/mob_grinding_utils.blocks.BlockDelightfulDirt.updateShape(BlockDelightfulDirt.java:57) ~[mob_grinding_utils-1.1.9+mc1.21.1.jar%23747!/:1.1.9+mc1.21.1]
	

Steps to reproduce

1 - Start a new world or travel to unexplored areas
2 - Generate a terrain that have
2 - The server crashes when generating new terrain (island with Mangrove tree

Players discovering those chunks are unable to relog because they crash the server as soon as they log in.

Full crash log : https://gist.github.com/SebGrd/ab42c772048dcca69f18457865939608
Chunk IO Error report: https://gist.github.com/SebGrd/bcc78818e2122148625c018f79c9973a

Mod Information

• Mod: Mob Grinding Utils
• Version: 1.1.9+mc1.21.1
• Minecraft: 1.21.1
• Loader: NeoForge 21.1.186
• Modpack: FTB Skies 2

Additional Notes

This seems to be related to how the mod handles world generation
The crash happens in the BlockDelightfulDirt component