BEFORE CONTINUING:

• Always check you are using the latest version of these mods and its dependencies
• Remove known problematic rendering mods such as Optifine, Sodium and others

Version-Loader

1.21.1-FABRIC

Moonlight Lib Version

1.21-2.17.12

Describe the Issue

Crashed when creating new world

Log Attachment

https://mclo.gs/2Z7CzQx

OPTIONAL: To Produce

No response

OPTIONAL: Which mods are affected?

Supplementaries

Try without other mods on with just supplementarirs

Didn't find which causes this, it's familiar to issue#277

meaning it happens or does not happens without other mods?

It only happens with cyanide mod

Yup. I know of this issue then. That mod is nuking other mod added Datapack registries. Are you sure you have it updated because about a year ago this was reported and I was sure they sai they fixed it. If not close this and open an issue on there again