Whenever I load into a save right after loading up the game, the seed for the Alfheim dimension is set to 0 instead of the world seed. On subsequent loads - e.g. returning to the main menu and opening the save again - the seed is set correctly. Once you quit the game and start it back up, the first load of the save will set the seed to 0 again.

I have verified this by checking the level.dat using NBTExplorer.

Since I first assumed this would be a mod conflict, I stripped it down to the bare minimum and was still able to reproduce the issue:

• Forge 40.0.44
• AutoRegLib-1.7-53
• Botania-1.18.2-430
• curios-forge-1.18.2-5.0.6.3
• LibX-1.18.2-3.2.9
• MythicBotany-1.18.2-2.1.1
• Patchouli-1.18.2-67