Crash code:
https://pastebin.com/4DcQm88Q

I'm getting the exact same error. I even started a new world & the game crashes before the new world finishes loading with the error:

The game crashed whilst exception in server tick loop
Error: java.lang.NoSuchMethodError: 'net.minecraft.nbt.CompoundTag com.stal111.valhelsia_structures.common.block.entity.JarBlockEntity.save(net.minecraft.nbt.CompoundTag)'
Exit Code: -1

Same to me

Same here

I was getting the same error. Reverted Valhelsia Core mod to the valhelsia_core-1.18.1-0.3.1.jar version (vs valhelsia_core-1.18.1-0.3.2.jar), and the error isn't happening anymore.

Closing this issue, duplicate of #119

For now, please either downgrade to Forge 39.0.44 or earlier, or wait for the next update.