https://paste.dimdev.org/amonosaboj.mccrash

Any reasons why you use not latest reborn core?

I have tested with latest RebornCore and it occurred too.

Part of the crash log seems to be missing, and for some reason the crash log is mapped?

Are you running this in a dev env? Or do you have a mod that changes the crashlog? Can you try without mods that alter the crashlog and see what you get?

I cannot reproduce this crash somehow (using Reborn Core 3.12.0 or 3.12.1) sorry : (

Not dev env. No that kind mod I think.

This is most certiantly still a bug

https://pastebin.com/xJVyYVen

My team members known about it for ages but " I have not had the time to report it " but has time to write a craft tweaker script

Not the same issue