Modpack version
1.61

Can the issue be reproduced?
yes

Logs
https://pastebin.com/pqRK3KsG

Issue
Mekanism null pointer exception
--> fixed in Mekanism-1.12.2-9.7.1.371.jar
(https://minecraft.curseforge.com/projects/mekanism/files/2699534)

Thanks for the report :)

Can you avoid this crash, or would a hotfix be nice?

I can't start the World anymore because it crashes instantaneously.
I tried updating Mekanism on my own but then strange things happened(like some items aren't craftable anymore), so a fix would be nice.

Mkay, fixing it now.