I'm not 100% sure but the newest versions of core crash for me. I'm doing some testing with disabling the update process right now and re running it. Loaded fine yesterday when I updated to 1.12.2 but I was online then.
Calling a ticking error. I will pastebin the issue to you in a bit if nothing fixes it.

Please send me the crashlog, not much I can do without it.

Ok cool give me a few minutes to put it up.

https://pastebin.com/gRFZ27LD
if you want me to i will do another run online to see if it loads correctly now that I am on my pc
i will also do a run offline without foamfix anarchy and use the lawful version or even without.
just let me know how i can help

Thanks! Will be fixed in next update.

It is version checking i believe.
Forge versioning comparable version parser
To default artifact version
To org.cyclops.'core.init.modbaseversionable.needs update
To '.'.tracking.versions.ontick
Then a bunch of fml and Minecraft references to entities and such.
If you want to see let me know.
Only happens when offline. Never did with 0.10.17 and back though.