I understand this is not a problem with vanilla Minecraft, and thus this should not be a high-priority issue. However, I would assume other mods that deal with being inside blocks would experience similar problems when used with Lithium.

Version Information

lithium-fabric-mc1.18.1-0.7.7.jar

Expected Behavior

Players using the Phantom origin from the Origins mod should be able to phase through the ground without suffocating.

Actual Behavior

Players using the Phantom origin from the Origins mod take suffocation damage while phasing through blocks.

Reproduction Steps

Install Origins for 1.18.1, as well as Lithium for 1.18.1. Go into a singleplayer world, and select the Phantom origin. Try to phase through blocks in survival or adventure.

Other Information

Other mods being used:
Farmer's Delight
Medieval Weapons
Extra Origins
Medieval Origins
Mob Origins
Simple Voice Chat

I think we had this exact same issue before. Adding mixin.entity.collisions.suffocation=false to the lithium properties file to disable the optimization might work around it

Hey, thanks! It reverted suffocation to vanilla. This will be a good solution for now.

Instructions on how to locate the file? I would also like to resolve this issue. Thank you in advance.

.minecraft/config/lithium.properties (open with a text editor)

This did not work for me. I am using the same mods as the original poster. The lithium conf file will not save or load. I tried stopping and starting the server I tried /reload. It doesnt work. What do I do?