The mod causes a crash when used together with the recommended version of VanillaFix. Seems to work with the development version of VanillaFix but that one has issues of its own with Bewitchment and possibly others.

Do you have any data on this incompatibility? Log files, crash logs etc? Also, which version of JEID is affected, and what version of Forge are you using?

Forge: 1.12.2-14.23.5.2847
VanillaFix: 1.0.10-99
JEID: 1.0.3-54

Downgrading JEID to version 1.0.3-48 fixed the issue.

The development version of VanillaFix does work but that one had issues with Bewitchment. I presume if they fix that and release their new version, there won't be a need to downgrade / fix JEID.

Im having the same problem as well, running a customized enigmatic 2 light pack
Crash Report: https://pastebin.com/2Qip9PQd

Same problem. Logs. (edit) To clarify, I also traced my crash to JEIDs, and have VanillaFix installed.
https://pastebin.com/27W6APm0 (crash)
https://pastebin.com/PFYB5Cw8 (debug)
https://pastebin.com/7V2E125K (latest)

Here too. mixins 0.8 causes it to crash leaving vanillafix to label it as an unknown mod as the potential cause.