The error occurs on 2 last versions of JEID (-54 and -55), on the -48 version there is no such error.
Here is the crash report: https://pastebin.com/RQEttytK

MalisisCore needs a new release to support Mixins 0.8, which the forked version already does, Dockter just needs to release it, so no issue here besides a mod needing a new release.

The problem still occurs even without MalisisCore and Doors.

Then please upload your full log so I can view it

Do you mean the debug.log?

No, I mean your normal game log

https://pastebin.com/Swxq3pSH Here it is

The issue is ForgeEssentials, which I don't know why they'd need Mixins, but okay.....if you're using that mod to replace Essentials on a server or what not, there's 2 server types: Magma and Mohist that can accomplish this no problem